Time Series Analysis Fourth Edition George E. P. Box
Time Series Analysis Fourth Edition George E. P. Box
Time Series Analysis Fourth Edition George E. P. Box
Time Series Analysis Fourth Edition George E. P. Box
1. Time Series Analysis Fourth Edition George E. P.
Box pdf download
https://ebookfinal.com/download/time-series-analysis-fourth-
edition-george-e-p-box/
Explore and download more ebooks or textbooks
at ebookfinal.com
2. We have selected some products that you may be interested in
Click the link to download now or visit ebookfinal.com
for more options!.
Time Series Analysis Forecasting and Control 4th Edition
George E.P. Box
https://ebookfinal.com/download/time-series-analysis-forecasting-and-
control-4th-edition-george-e-p-box/
Statistical Control by Monitoring and Adjustment Second
Edition George E. P. Box
https://ebookfinal.com/download/statistical-control-by-monitoring-and-
adjustment-second-edition-george-e-p-box/
Response Surfaces Mixtures and Ridge Analyses 2nd ed
Edition George E. P. Box
https://ebookfinal.com/download/response-surfaces-mixtures-and-ridge-
analyses-2nd-ed-edition-george-e-p-box/
Nonlinear Time Series Analysis 2nd Edition Holger Kantz
https://ebookfinal.com/download/nonlinear-time-series-analysis-2nd-
edition-holger-kantz/
3. A Course in Time Series Analysis 1st Edition Pena D.
https://ebookfinal.com/download/a-course-in-time-series-analysis-1st-
edition-pena-d/
Time Series Analysis by State Space Methods 2nd Edition
Durbin J.
https://ebookfinal.com/download/time-series-analysis-by-state-space-
methods-2nd-edition-durbin-j/
Basic Data Analysis for Time Series with R 1st Edition
Dewayne R. Derryberry
https://ebookfinal.com/download/basic-data-analysis-for-time-series-
with-r-1st-edition-dewayne-r-derryberry/
Time Series Data Analysis Using EViews Statistics in
Practice I. Gusti Ngurah Agung
https://ebookfinal.com/download/time-series-data-analysis-using-
eviews-statistics-in-practice-i-gusti-ngurah-agung/
The Study of Language Fourth Edition George Yule
https://ebookfinal.com/download/the-study-of-language-fourth-edition-
george-yule/
5. Time Series Analysis Fourth Edition George E. P. Box
Digital Instant Download
Author(s): George E. P. Box, GwilymM. Jenkins, Gregory C. Reinsel(auth.)
ISBN(s): 9781118619193, 1118619196
File Details: PDF, 6.95 MB
Year: 2008
Language: english
7. WILEY SERIES IN PROBABILITY AND STATISTICS
Established by WALTER A. SHEWHART and SAMUEL S. WILKS
Editors: David J. Balding, Noel A. C. Cressie, Garrett M. Fitzmaurice,
Iain M. Johnstone, Geert Molenberghs, David W. Scott, Adrian F. M. Smith,
Ruey S. Tsay, Sanford Weisberg
Editors Emeriti: Vic Barnett, J. Stuart Hunter, Jozef L. Teugels
A complete list of the titles in this series appears at the end of this volume.
8. Time Series Analysis
Forecasting and Control
FOURTH EDITION
GEORGE E. P. BOX
GWILYM M. JENKINS
GREGORY C. REINSEL
A JOHN WILEY & SONS, INC., PUBLICATION
9. Copyright 2008 by John Wiley & Sons, Inc. All rights reserved.
Published by John Wiley & Sons, Inc., Hoboken, New Jersey.
Published simultaneously in Canada.
No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form
or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as
permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior
written permission of the Publisher, or authorization through payment of the appropriate per-copy fee
to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400,
fax (978) 750-4470, or on the web at www.copyright.com. Requests to the Publisher for permission
should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street,
Hoboken, NJ 07030, (201) 748-6011, fax (201) 748-6008, or online at
http://www.wiley.com/go/permission.
Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts
in preparing this book, they make no representations or warranties with respect to the accuracy or
completeness of the contents of this book and specifically disclaim any implied warranties of
merchantability or fitness for a particular purpose. No warranty may be created or extended by sales
representatives or written sales materials. The advice and strategies contained herein may not be
suitable for your situation. You should consult with a professional where appropriate. Neither the
publisher nor author shall be liable for any loss of profit or any other commercial damages, including
but not limited to special, incidental, consequential, or other damages.
For general information on our other products and services or for technical support, please contact our
Customer Care Department within the United States at (800) 762-2974, outside the United States at
(317) 572-3993 or fax (317) 572-4002.
Wiley also publishes its books in a variety of electronic formats. Some content that appears in print
may not be available in electronic formats. For more information about Wiley products, visit our web
site at www.wiley.com.
Library of Congress Cataloging-in-Publication Data:
Box, George E. P.
Time series analysis : forecasting and control / George E.P. Box, Gwilym M.
Jenkins, Gregory C. Reinsel. —4th ed.
p. cm.
Includes index.
ISBN-978-0-470-27284-8 (cloth)
1. Time-series analysis. 2. Predicition theory. 3. Transfer functions. 4.
Feedback control systems—Mathematical models. I. Jenkins, Gwilym M. II.
Reinsel, Gregory C. III. Title
QA280.B67 2008
519.55—dc22
2007044569
Printed in the United States of America
10 9 8 7 6 5 4 3 2 1
10. To the memory of
Gwilym M. Jenkins Gregory C. Reinsel
11. Contents
Preface to the Fourth Edition xxi
Preface to the Third Edition xxiii
1 Introduction 1
1.1 Five Important Practical Problems, 2
1.1.1 Forecasting Time Series, 2
1.1.2 Estimation of Transfer Functions, 3
1.1.3 Analysis of Effects of Unusual Intervention
Events to a System, 4
1.1.4 Analysis of Multivariate Time Series, 5
1.1.5 Discrete Control Systems, 5
1.2 Stochastic and Deterministic Dynamic Mathematical
Models, 7
1.2.1 Stationary and Nonstationary Stochastic Models
for Forecasting and Control, 7
1.2.2 Transfer Function Models, 12
1.2.3 Models for Discrete Control Systems, 14
1.3 Basic Ideas in Model Building, 16
1.3.1 Parsimony, 16
1.3.2 Iterative Stages in the Selection of a Model, 17
Part One Stochastic Models and Their Forecasting 19
2 Autocorrelation Function and Spectrum of Stationary Processes 21
2.1 Autocorrelation Properties of Stationary Models, 21
2.1.1 Time Series and Stochastic Processes, 21
2.1.2 Stationary Stochastic Processes, 24
vii
12. viii CONTENTS
2.1.3 Positive Definiteness and the Autocovariance
Matrix, 25
2.1.4 Autocovariance and Autocorrelation
Functions, 29
2.1.5 Estimation of Autocovariance and
Autocorrelation Functions, 31
2.1.6 Standard Errors of Autocorrelation Estimates, 33
2.2 Spectral Properties of Stationary Models, 35
2.2.1 Periodogram of a Time Series, 35
2.2.2 Analysis of Variance, 37
2.2.3 Spectrum and Spectral Density Function, 38
2.2.4 Simple Examples of Autocorrelation and Spectral
Density Functions, 43
2.2.5 Advantages and Disadvantages of the
Autocorrelation and Spectral Density
Functions, 45
A2.1 Link between the Sample Spectrum and Autocovariance
Function Estimate, 45
3 Linear Stationary Models 47
3.1 General Linear Process, 47
3.1.1 Two Equivalent Forms for the Linear Process, 47
3.1.2 Autocovariance Generating Function of a Linear
Process, 50
3.1.3 Stationarity and Invertibility Conditions for a
Linear Process, 51
3.1.4 Autoregressive and Moving Average
Processes, 53
3.2 Autoregressive Processes, 55
3.2.1 Stationarity Conditions for Autoregressive
Processes, 55
3.2.2 Autocorrelation Function and Spectrum of
Autoregressive Processes, 57
3.2.3 First-Order Autoregressive (Markov) Process, 59
3.2.4 Second-Order Autoregressive Process, 61
3.2.5 Partial Autocorrelation Function, 66
3.2.6 Estimation of the Partial Autocorrelation
Function, 69
3.2.7 Standard Errors of Partial Autocorrelation
Estimates, 70
3.3 Moving Average Processes, 71
13. CONTENTS ix
3.3.1 Invertibility Conditions for Moving Average
Processes, 71
3.3.2 Autocorrelation Function and Spectrum of
Moving Average Processes, 72
3.3.3 First-Order Moving Average Process, 73
3.3.4 Second-Order Moving Average Process, 75
3.3.5 Duality Between Autoregressive and Moving
Average Processes, 78
3.4 Mixed Autoregressive–Moving Average Processes, 79
3.4.1 Stationarity and Invertibility Properties, 79
3.4.2 Autocorrelation Function and Spectrum of Mixed
Processes, 80
3.4.3 First-Order Autoregressive–First-Order Moving
Average Process, 82
3.4.4 Summary, 86
A3.1 Autocovariances, Autocovariance Generating Function, and
Stationarity Conditions for a General Linear Process, 86
A3.2 Recursive Method for Calculating Estimates of
Autoregressive Parameters, 89
4 Linear Nonstationary Models 93
4.1 Autoregressive Integrated Moving Average Processes, 93
4.1.1 Nonstationary First-Order Autoregressive
Process, 93
4.1.2 General Model for a Nonstationary Process
Exhibiting Homogeneity, 95
4.1.3 General Form of the Autoregressive Integrated
Moving Average Model, 100
4.2 Three Explicit Forms for The Autoregressive Integrated
Moving Average Model, 103
4.2.1 Difference Equation Form of the Model, 103
4.2.2 Random Shock Form of the Model, 104
4.2.3 Inverted Form of the Model, 111
4.3 Integrated Moving Average Processes, 114
4.3.1 Integrated Moving Average Process of
Order (0, 1, 1), 115
4.3.2 Integrated Moving Average Process of
Order (0, 2, 2), 119
4.3.3 General Integrated Moving Average Process of
Order (0, d, q), 123
A4.1 Linear Difference Equations, 125
A4.2 IMA(0, 1, 1) Process with Deterministic Drift, 131
14. x CONTENTS
A4.3 Arima Processes with Added Noise, 131
A4.3.1 Sum of Two Independent Moving Average
Processes, 132
A4.3.2 Effect of Added Noise on the General
Model, 133
A4.3.3 Example for an IMA(0, 1, 1) Process with Added
White Noise, 134
A4.3.4 Relation between the IMA(0, 1, 1) Process and a
Random Walk, 135
A4.3.5 Autocovariance Function of the General Model
with Added Correlated Noise, 135
5 Forecasting 137
5.1 Minimum Mean Square Error Forecasts and Their
Properties, 137
5.1.1 Derivation of the Minimum Mean Square Error
Forecasts, 139
5.1.2 Three Basic Forms for the Forecast, 141
5.2 Calculating and Updating Forecasts, 145
5.2.1 Convenient Format for the Forecasts, 145
5.2.2 Calculation of the ψ Weights, 147
5.2.3 Use of the ψ Weights in Updating the
Forecasts, 148
5.2.4 Calculation of the Probability Limits of the
Forecasts at Any Lead Time, 150
5.3 Forecast Function and Forecast Weights, 152
5.3.1 Eventual Forecast Function Determined by the
Autoregressive Operator, 152
5.3.2 Role of the Moving Average Operator in Fixing
the Initial Values, 153
5.3.3 Lead l Forecast Weights, 154
5.4 Examples of Forecast Functions and Their Updating, 157
5.4.1 Forecasting an IMA(0, 1, 1) Process, 157
5.4.2 Forecasting an IMA(0, 2, 2) Process, 160
5.4.3 Forecasting a General IMA(0, d, q) Process, 163
5.4.4 Forecasting Autoregressive Processes, 164
5.4.5 Forecasting a (1, 0, 1) Process, 167
5.4.6 Forecasting a (1, 1, 1) Process, 169
15. CONTENTS xi
5.5 Use of State-Space Model Formulation for Exact
Forecasting, 170
5.5.1 State-Space Model Representation for the
ARIMA Process, 170
5.5.2 Kalman Filtering Relations for Use
in Prediction, 171
5.5.3 Smoothing Relations in the State Variable
Model, 175
5.6 Summary, 177
A5.1 Correlations Between Forecast Errors, 180
A5.1.1 Autocorrelation Function of Forecast Errors at
Different Origins, 180
A5.1.2 Correlation Between Forecast Errors at the Same
Origin with Different Lead Times, 182
A5.2 Forecast Weights for Any Lead Time, 182
A5.3 Forecasting in Terms of the General Integrated Form, 185
A5.3.1 General Method of Obtaining the Integrated
Form, 185
A5.3.2 Updating the General Integrated Form, 187
A5.3.3 Comparison with the Discounted Least Squares
Method, 187
Part Two Stochastic Model Building 193
6 Model Identification 195
6.1 Objectives of Identification, 195
6.1.1 Stages in the Identification Procedure, 195
6.2 Identification Techniques, 196
6.2.1 Use of the Autocorrelation and Partial
Autocorrelation Functions in Identification, 196
6.2.2 Standard Errors for Estimated Autocorrelations
and Partial Autocorrelations, 198
6.2.3 Identification of Some Actual Time Series, 200
6.2.4 Some Additional Model Identification Tools, 208
6.3 Initial Estimates for the Parameters, 213
6.3.1 Uniqueness of Estimates Obtained from the
Autocovariance Function, 213
6.3.2 Initial Estimates for Moving Average
Processes, 213
6.3.3 Initial Estimates for Autoregressive
Processes, 215
16. xii CONTENTS
6.3.4 Initial Estimates for Mixed
Autoregressive–Moving Average Processes, 216
6.3.5 Initial Estimate of Error Variance, 218
6.3.6 Approximate Standard Error for w, 218
6.3.7 Choice Between Stationary and Nonstationary
Models in Doubtful Cases, 220
6.4 Model Multiplicity, 221
6.4.1 Multiplicity of Autoregressive–Moving Average
Models, 221
6.4.2 Multiple Moment Solutions for Moving Average
Parameters, 224
6.4.3 Use of the Backward Process to Determine
Starting Values, 225
A6.1 Expected Behavior of the Estimated Autocorrelation
Function for a Nonstationary Process, 225
A6.2 General Method for Obtaining Initial Estimates of the
Parameters of a Mixed Autoregressive–Moving Average
Process, 226
7 Model Estimation 231
7.1 Study of the Likelihood and Sum-of-Squares Functions, 231
7.1.1 Likelihood Function, 231
7.1.2 Conditional Likelihood for an ARIMA
Process, 232
7.1.3 Choice of Starting Values for Conditional
Calculation, 234
7.1.4 Unconditional Likelihood; Sum-of-Squares
Function; Least Squares Estimates, 235
7.1.5 General Procedure for Calculating the
Unconditional Sum of Squares, 240
7.1.6 Graphical Study of the Sum-of-Squares
Function, 245
7.1.7 Description of “Well-Behaved” Estimation
Situations; Confidence Regions, 248
7.2 Nonlinear Estimation, 255
7.2.1 General Method of Approach, 255
7.2.2 Numerical Estimates of the Derivatives, 257
7.2.3 Direct Evaluation of the Derivatives, 258
7.2.4 General Least Squares Algorithm for the
Conditional Model, 260
7.2.5 Summary of Models Fitted to Series A to F, 263
17. CONTENTS xiii
7.2.6 Large-Sample Information Matrices and
Covariance Estimates, 264
7.3 Some Estimation Results for Specific Models, 268
7.3.1 Autoregressive Processes, 268
7.3.2 Moving Average Processes, 270
7.3.3 Mixed Processes, 271
7.3.4 Separation of Linear and Nonlinear Components
in Estimation, 271
7.3.5 Parameter Redundancy, 273
7.4 Likelihood Function Based on the State-Space Model, 275
7.5 Unit Roots in Arima Models, 280
7.5.1 Formal Tests for Unit Roots in AR Models, 281
7.5.2 Extensions of Unit-Root Testing to Mixed
ARIMA Models, 286
7.6 Estimation Using Bayes’s Theorem, 287
7.6.1 Bayes’s Theorem, 287
7.6.2 Bayesian Estimation of Parameters, 289
7.6.3 Autoregressive Processes, 290
7.6.4 Moving Average Processes, 293
7.6.5 Mixed Processes, 294
A7.1 Review of Normal Distribution Theory, 296
A7.1.1 Partitioning of a Positive-Definite Quadratic
Form, 296
A7.1.2 Two Useful Integrals, 296
A7.1.3 Normal Distribution, 297
A7.1.4 Student’s t Distribution, 300
A7.2 Review of Linear Least Squares Theory, 303
A7.2.1 Normal Equations and Least Squares, 303
A7.2.2 Estimation of Error Variance, 304
A7.2.3 Covariance Matrix of Least Squares
Estimates, 305
A7.2.4 Confidence Regions, 305
A7.2.5 Correlated Errors, 305
A7.3 Exact Likelihood Function for Moving Average and Mixed
Processes, 306
A7.4 Exact Likelihood Function for an Autoregressive
Process, 314
A7.5 Asymptotic Distribution of Estimators for Autoregressive
Models, 323
18. xiv CONTENTS
A7.6 Examples of the Effect of Parameter Estimation Errors on
Variances of Forecast Errors and Probability Limits for
Forecasts, 327
A7.7 Special Note on Estimation of Moving Average
Parameters, 330
8 Model Diagnostic Checking 333
8.1 Checking the Stochastic Model, 333
8.1.1 General Philosophy, 333
8.1.2 Overfitting, 334
8.2 Diagnostic Checks Applied to Residuals, 335
8.2.1 Autocorrelation Check, 337
8.2.2 Portmanteau Lack-of-Fit Test, 338
8.2.3 Model Inadequacy Arising from Changes in
Parameter Values, 343
8.2.4 Score Tests for Model Checking, 344
8.2.5 Cumulative Periodogram Check, 347
8.3 Use of Residuals to Modify the Model, 350
8.3.1 Nature of the Correlations in the Residuals When
an Incorrect Model Is Used, 350
8.3.2 Use of Residuals to Modify the Model, 352
9 Seasonal Models 353
9.1 Parsimonious Models for Seasonal Time Series, 353
9.1.1 Fitting versus Forecasting, 353
9.1.2 Seasonal Models Involving Adaptive Sines and
Cosines, 354
9.1.3 General Multiplicative Seasonal Model, 356
9.2 Representation of the Airline Data by a Multiplicative
(0, 1, 1) × (0, 1, 1)12 Model, 359
9.2.1 Multiplicative (0, 1, 1) ×(0, 1, 1)12 Model, 359
9.2.2 Forecasting, 360
9.2.3 Identification, 367
9.2.4 Estimation, 370
9.2.5 Diagnostic Checking, 375
9.3 Some Aspects of More General Seasonal ARIMA
Models, 375
9.3.1 Multiplicative and Nonmultiplicative
Models, 375
9.3.2 Identification, 379
19. CONTENTS xv
9.3.3 Estimation, 380
9.3.4 Eventual Forecast Functions for Various Seasonal
Models, 381
9.3.5 Choice of Transformation, 383
9.4 Structural Component Models and Deterministic Seasonal
Components, 384
9.4.1 Structural Component Time Series Models, 384
9.4.2 Deterministic Seasonal and Trend Components
and Common Factors, 388
9.4.3 Estimation of Unobserved Components in
Structural Models, 390
9.5 Regression Models with Time Series Error Terms, 397
9.5.1 Model Building, Estimation, and Forecasting
Procedures for Regression Models, 399
9.5.2 Restricted Maximum Likelihood Estimation for
Regression Models, 404
A9.1 Autocovariances for Some Seasonal Models, 407
10 Nonlinear and Long Memory Models 413
10.1 Autoregressive Conditional Heteroscedastic (ARCH)
Models, 413
10.1.1 First-Order ARCH Model, 415
10.1.2 Consideration for More General Models, 416
10.1.3 Model Building and Parameter Estimation, 417
10.2 Nonlinear Time Series Models, 420
10.2.1 Classes of Nonlinear Models, 421
10.2.2 Implications and Examples of Nonlinear
Models, 424
10.3 Long Memory Time Series Processes, 428
10.3.1 Fractionally Integrated Processes, 429
10.3.2 Estimation of Parameters, 433
Part Three Transfer Function and Multivariate Model
Building 437
11 Transfer Function Models 439
11.1 Linear Transfer Function Models, 439
11.1.1 Discrete Transfer Function, 439
11.1.2 Continuous Dynamic Models Represented
by Differential Equations, 442
20. xvi CONTENTS
11.2 Discrete Dynamic Models Represented by Difference
Equations, 447
11.2.1 General Form of the Difference Equation, 447
11.2.2 Nature of the Transfer Function, 449
11.2.3 First- and Second-Order Discrete Transfer
Function Models, 450
11.2.4 Recursive Computation of Output for Any
Input, 456
11.2.5 Transfer Function Models with Added Noise, 458
11.3 Relation Between Discrete and Continuous Models, 458
11.3.1 Response to a Pulsed Input, 459
11.3.2 Relationships for First- and Second-Order
Coincident Systems, 461
11.3.3 Approximating General Continuous Models by
Discrete Models, 464
A11.1 Continuous Models with Pulsed Inputs, 465
A11.2 Nonlinear Transfer Functions and Linearization, 470
12 Identification, Fitting, and Checking of Transfer Function Models 473
12.1 Cross-Correlation Function, 474
12.1.1 Properties of the Cross-Covariance and
Cross-Correlation Functions, 474
12.1.2 Estimation of the Cross-Covariance and
Cross-Correlation Functions, 477
12.1.3 Approximate Standard Errors of
Cross-Correlation Estimates, 478
12.2 Identification of Transfer Function Models, 481
12.2.1 Identification of Transfer Function Models by
Prewhitening the Input, 483
12.2.2 Example of the Identification of a Transfer
Function Model, 484
12.2.3 Identification of the Noise Model, 488
12.2.4 Some General Considerations in Identifying
Transfer Function Models, 490
12.3 Fitting and Checking Transfer Function Models, 492
12.3.1 Conditional Sum-of-Squares Function, 492
12.3.2 Nonlinear Estimation, 495
12.3.3 Use of Residuals for Diagnostic Checking, 497
12.3.4 Specific Checks Applied to the Residuals, 498
12.4 Some Examples of Fitting and Checking Transfer Function
Models, 501
21. CONTENTS xvii
12.4.1 Fitting and Checking of the Gas Furnace
Model, 501
12.4.2 Simulated Example with Two Inputs, 507
12.5 Forecasting With Transfer Function Models Using Leading
Indicators, 509
12.5.1 Minimum Mean Square Error Forecast, 510
12.5.2 Forecast of CO2 Output from Gas Furnace, 514
12.5.3 Forecast of Nonstationary Sales Data Using a
Leading Indicator, 517
12.6 Some Aspects of the Design of Experiments to Estimate
Transfer Functions, 519
A12.1 Use of Cross Spectral Analysis for Transfer Function Model
Identification, 521
A12.1.1 Identification of Single Input Transfer Function
Models, 521
A12.1.2 Identification of Multiple Input Transfer Function
Models, 523
A12.2 Choice of Input to Provide Optimal Parameter
Estimates, 524
A12.2.1 Design of Optimal Inputs for a Simple
System, 524
A12.2.2 Numerical Example, 527
13 Intervention Analysis Models and Outlier Detection 529
13.1 Intervention Analysis Methods, 529
13.1.1 Models for Intervention Analysis, 529
13.1.2 Example of Intervention Analysis, 532
13.1.3 Nature of the MLE for a Simple Level Change
Parameter Model, 533
13.2 Outlier Analysis for Time Series, 536
13.2.1 Models for Additive and Innovational
Outliers, 537
13.2.2 Estimation of Outlier Effect for Known Timing
of the Outlier, 538
13.2.3 Iterative Procedure for Outlier Detection, 540
13.2.4 Examples of Analysis of Outliers, 541
13.3 Estimation for ARMA Models with Missing Values, 543
13.3.1 State-Space Model and Kalman Filter with
Missing Values, 544
13.3.2 Estimation of Missing Values of an ARMA
Process, 546
22. xviii CONTENTS
14 Multivariate Time Series Analysis 551
14.1 Stationary Multivariate Time Series, 552
14.1.1 Covariance Properties of Stationary Multivariate
Time Series, 552
14.1.2 Spectral Characteristics for Stationary
Multivariate Processes, 554
14.1.3 Linear Filtering Relations for Stationary
Multivariate Processes, 555
14.2 Linear Model Representations for Stationary Multivariate
Processes, 556
14.2.1 Vector Autoregressive–Moving Average (ARMA)
Models and Representations, 557
14.2.2 Aspects of Nonuniqueness and Parameter
Identifiability for Vector ARMA Models, 563
14.2.3 Echelon Canonical Form of the Vector ARMA
Model, 565
14.2.4 Relation of Vector ARMA to Transfer Function
and ARMAX Model Forms, 569
14.3 Nonstationary Vector Autoregressive–Moving Average
Models, 570
14.4 Forecasting for Vector Autoregressive–Moving Average
Processes, 573
14.4.1 Calculation of Forecasts from ARMA Difference
Equation, 573
14.4.2 Forecasts from Infinite MA Form and Properties
of Forecast Errors, 575
14.5 State-Space Form of the Vector ARMA Model, 575
14.6 Statistical Analysis of Vector ARMA Models, 578
14.6.1 Initial Model Building and Least Squares for
Vector AR Models, 578
14.6.2 Estimation and Model Checking for Vector
ARMA Models, 583
14.6.3 Estimation and Inferences for Co-integrated
Vector AR Models, 585
14.7 Example of Vector ARMA Modeling, 588
Part Four Design of Discrete Control Schemes 597
15 Aspects of Process Control 599
15.1 Process Monitoring and Process Adjustment, 600
15.1.1 Process Monitoring, 600
23. CONTENTS xix
15.1.2 Process Adjustment, 603
15.2 Process Adjustment Using Feedback Control, 604
15.2.1 Feedback Adjustment Chart, 605
15.2.2 Modeling the Feedback Loop, 607
15.2.3 Simple Models for Disturbances and Dynamics,
608
15.2.4 General Minimum Mean Square Error Feedback
Control Schemes, 612
15.2.5 Manual Adjustment for Discrete
Proportional–Integral Schemes, 615
15.2.6 Complementary Roles of Monitoring and
Adjustment, 617
15.3 Excessive Adjustment Sometimes Required by MMSE
Control, 620
15.3.1 Constrained Control, 621
15.4 Minimum Cost Control with Fixed Costs of Adjustment and
Monitoring, 623
15.4.1 Bounded Adjustment Scheme for Fixed
Adjustment Cost, 623
15.4.2 Indirect Approach for Obtaining a Bounded
Adjustment Scheme, 625
15.4.3 Inclusion of the Cost of Monitoring, 627
15.5 Feedforward Control, 627
15.5.1 Feedforward Control to Minimize Mean Square
Error at the Output, 629
15.5.2 An Example—Control of the Specific Gravity of
an Intermediate Product, 632
15.5.3 Feedforward Control with Multiple Inputs, 635
15.5.4 Feedforward–Feedback Control, 636
15.5.5 Advantages and Disadvantages of Feedforward
and Feedback Control, 638
15.5.6 Remarks on Fitting Transfer Function–Noise
Models Using Operating Data, 639
15.6 Monitoring Values of Parameters of Forecasting and
Feedback Adjustment Schemes, 642
A15.1 Feedback Control Schemes Where the Adjustment Variance
is Restricted, 644
A15.1.1 Derivation of Optimal Adjustment, 644
A15.2 Choice of the Sampling Interval, 653
A15.2.1 Illustration of the Effect of Reducing Sampling
Frequency, 654
A15.2.2 Sampling an IMA(0, 1, 1) Process, 654
24. xx CONTENTS
Part Five Charts and Tables 659
Collection of Tables and Charts 661
Collection of Time Series Used for Examples in the Text
and in Exercises 669
References 685
Part Six Exercises and Problems 701
Index 729
25. Preface to the Fourth Edition
It may be of interest to briefly recount how this book came to be written. Gwilym
Jenkins and I first became friends in the late 1950s. We were intrigued by an
idea that a chemical reactor could be designed that optimized itself automatically
and could follow a moving maximum. We both believed that many advances in
statistical theory came about as a result of interaction with researchers who were
working on real scientific problems. Helping to design and build such a reactor
would present an opportunity to further demonstrate this concept.
When Gwilym Jenkins came to visit Madison for a year, we discussed the idea
with the famous chemical engineer Olaf Hougen, then in his eighties. He was
enthusiastic and suggested that we form a small team in a joint project to build
such a system. The National Science Foundation later supported this project. It took
three years, but suffice it to say, that after many experiments, several setbacks, and
some successes the reactor was built and it worked.
As expected this investigation taught us a lot. In particular we acquired profi-
ciency in the manipulation of difference equations that were needed to characterize
the dynamics of the system. It also gave us a better understanding of nonstationary
time series required for realistic modeling of system noise. This was a happy time.
We were doing what we most enjoyed doing: interacting with experimenters in the
evolution of ideas and the solution of real problems, with real apparatus and real
data.
Later there was fallout in other contexts, for example, advances in time series
analysis, in forecasting for business and economics, and also developments in
statistical process control (SPC) using some notions learned from the engineers.
Originally Gwilym came for a year. After that I spent each summer with him
in England at his home in Lancaster. For the rest of the year, we corresponded
using small reel-to-reel tape recorders. We wrote a number of technical reports
and published some papers but eventually realized we needed a book. The first
two editions of this book were written during a period in which Gwilym was,
with extraordinary courage, fighting a debilitating illness to which he succumbed
sometime after the book had been completed.
Later Gregory Reinsel, who had profound knowledge of the subject, helped to
complete the third edition. Also in this fourth edition, produced after his untimely
xxi
27. Foundation of
Aversa, 1030.
The sons of
Tancred of
Hauteville.
Conquest of Apulia,
1041–2.
1022 [see page 50], he found his chief obstacle in the new Greek
fortress of Troja, obstinately defended by some valiant Normans in
the pay of their old foe the Catapan.
Other Normans now flocked to the land of promise. Among these
was a chieftain named Ranulf, who joined Sergius, Prince of Naples,
a vassal of the Greeks, in his war against the Lombard prince Pandulf
of Capua. In reward for his services Ranulf received one of the
richest districts of the Terra di Lavoro, where he built in 1030 a town
named Aversa, the first Norman settlement in Italy. This foundation
makes a new departure in Norman policy.
The Normans no longer came to Italy as
isolated adventurers willing to sell their swords to the highest bidder.
By much the same arts as those by which their brethren later got
hold of the fairest parts of Wales and Ireland, the adventurers strove
to carve feudal states for themselves out of the chaos of southern
Italy. Whilst cleverly utilising the feuds that raged around them, they
pursued their interests with such dexterity, courage, and clear-
headed selfishness, that brilliant success soon crowned their efforts.
Conrad II. sojourned at Capua in 1038, deposed Pandulf and
confirmed Ranulf in the possession of Aversa, which he erected into
a county owing homage to the Western Emperor. Three of the twelve
sons of the Norman lord, Tancred of Hauteville, now left their scanty
patrimony in the Côtentin and joined the Normans in Italy. Their
names were William of the Iron Arm, Drogo, and Humphrey. In
1038 they joined the Greeks under George
Maniaces in an attempt to expel the
Mohammedans from Sicily. Messina and
Syracuse were captured, but an affront to their companion-in-arms
Ardouin drove the Normans back to the mainland in the moment of
victory, and led them to wreak their vengeance on the Greeks by a
strange compound of violence and treachery. Ardouin their friend
took the Greek pay and became governor of Melfi, the key of Apulia.
He proposed to the Normans that he should deliver Melfi to them,
and make that a starting-point for the conquest of Apulia, which he
proposed to divide between them and himself. The northerners
accepted his proposals. In 1041 Melfi was
delivered into their hands, and a long war
broke out between them and their former allies. By shrewdly putting
Adenulfus, the Lombard Duke of Benevento at the head of their
28. Robert Guiscard.
Leo IX. turns
against the
Normans.
armies, the Normans got allies that were probably necessary in the
early years of the struggle. But they were soon strong enough to
repudiate their associate. The divisions of the Greeks further
facilitated their task. In 1042 William of the Iron Arm was
proclaimed lord of the Normans of Apulia, with Melfi as the centre of
his power.
In 1046 William of Apulia died, and Drogo, his brother, succeeded
him. Henry III., then in Italy, recognised Drogo as Count of Apulia,
while renewing the grant of Aversa to another Ranulf. He also urged
the Normans to drive out of Benevento the Lombards, who after the
spread of the Norman power were making common cause with the
Greeks. About this time a fourth son of
Tancred of Hauteville came to Italy, where
he soon made himself the hero of the Norman conquerors. Anna
Comnena, the literary daughter of the Emperor Alexius, describes
Robert Guiscard as he appeared to his enemies. ‘His high stature
excelled that of the most mighty warriors. His complexion was
ruddy, his hair fair, his shoulders broad, his eyes flashed fire. It is
said that his voice was like the voice of a whole multitude, and could
put to flight an army of sixty thousand men.’ A poor gentleman’s son,
Robert was consumed by ambition to do great deeds, and joined to
great bravery and strength an extraordinary subtlety of spirit. His
surname of Guiscard is thought to testify to his ability and craft.
Badly received by his brothers in Apulia, he was reduced to taking
service with the Prince of Capua against his rival of Salerno. Events
soon gave him an opportunity of striking a blow for himself.
Meanwhile, a formidable combination was forming against the
Normans. Argyrus, son of Meles, had deserted his father’s policy and
came from Constantinople, as Patrician and Catapan (Governor),
with special commissions from the Emperor. Unable to persuade the
Normans to take service with the Emperor
against the Persians, he soon waged war
openly against them, and procured the
murder of Count Drogo in 1051, but was soon driven to take refuge in
Bari. Meanwhile Leo IX. had become Pope, and his all-absorbing
curiosity had led him to two journeys into southern Italy, where he
persuaded the inhabitants of Benevento to accept the protection of
the Holy See against the dreaded Northmen. It looked as if the
29. Battle of Civitate,
1053.
Peace between the
Normans and the
Pope.
Eastern and Western Empires were likely to combine with the
Papacy and the Lombards to get rid of the restless adventurers. In
1052 Henry III. granted the duchy of Benevento to the Roman
Church, and Leo hurried from Hungary to southern Italy to enforce
his claims on his new possession.
In May 1053 Leo IX. reached Monte
Casino. There soon flocked round him a
motley army, drawn together from every district of central and
southern Italy and eager to uphold the Holy Father against the
Norman usurpers; but the few hundred Germans, who had followed
the Pope over the Alps, were probably more serviceable in the field
than the mixed multitude of Italians. The Normans, abandoned by
their allies, united all their scanty forces for a decisive struggle. The
armies met on 18th June near Civitate (Civitella) on the banks of the
Fortore, the place of the first Norman victory in Italy. The longhaired
and gigantic Germans affected to despise their diminutive Norman
foes, and the fiercest fight was fought between the Pope’s fellow-
countrymen and Humphrey of Hauteville, the new Count of Apulia,
who commanded the Norman right. There the Norman horse long
sought in vain to break up the serried phalanx of the German
infantry. But the left and centre of the Normans, led respectively by
Richard, the new Count of Aversa, and Robert Guiscard, easily
scattered the enemies before them, and, returning in good time from
the pursuit, enabled Humphrey to win a final victory over the
Germans. Leo IX. barely escaped with his liberty from the fatal field.
Peter Damiani and the zealots denounced him for his unseemly
participation in acts of violence, and the object which had induced
him to depart from his sacred calling had been altogether unfulfilled.
He retired to Benevento, where he soon
came to an understanding with the
Normans, giving them his apostolic blessing
and absolving them from their blood-guiltiness. Even in the moment
of victory the Normans had shown every respect to the head of the
Church, and self-interest now combined with enthusiasm to make
them his friends. But Leo entered into no formal treaty with them.
He remained at Benevento, carefully watching their movements and
corresponding with Constantine Monomachus in the hope of
renewing the league against them. But his dealings with the Greek
Empire soon broke down owing to the theological differences which
30. Victor II., 1054–
1057.
Henry III.’s last
visit to Italy, 1055.
Position of the
Countess Matilda.
the acute hostility of Leo and Michael Cærularius now brought to a
head. Leo gave up all hope of western help when he fulminated the
excommunication against Cærularius, which led at once to the final
split of Catholic and Orthodox. In the spring of 1054 he returned to
Rome and died. His exploits and holy life had given him a great
reputation for holiness, and he was canonised as a saint. Even the
disaster of Civitate and the eastern schism did little to diminish his
glory.
Leo IX.’s successor as Pope was another
German, Gebhard, bishop of Eichstädt, who
took the name of Victor II. (1054–1057). He continued to work on the
lines of Pope Leo, though more in the spirit of a politician. During
Victor’s pontificate, Henry III. made his second and last visit to Italy
(1055). His presence was highly necessary.
His strongest Italian enemy, the powerful
Marquis Boniface of Tuscany, was dead, leaving an only daughter
Matilda heiress of his great inheritance. Boniface’s widow Beatrice
soon found a second husband in Godfrey the Bearded, Duke of Lower
Lorraine, the chief enemy of Henry in Germany. In this union there
was a danger of the German and Italian opposition to the Empire
being combined. But the formidable league dissolved at once on
Henry’s appearance. Godfrey fled from Italy, and Beatrice and her
daughter were led into honourable captivity in Germany. Godfrey’s
brother Frederick, hitherto a scheming ecclesiastic, renounced the
world, and became one of the most zealous of the monks of Monte
Casino. But the death of the Emperor and the long minority that
followed, soon restored the power of the heiress of Boniface. The
Countess Matilda, powerful alike in Tuscany and north of the
Apennines, became the most zealous of the allies of the Papacy. Her
support gave that material assistance
without which the purely spiritual aims of
the Papacy could hardly prevail. At the moment when the Papacy
had permanently absorbed the teachings of Cluny, it was a matter of
no small moment that the greatest temporal power of middle Italy
was on its side. It was a solid compensation for Leo’s failure against
the Normans.
31. Hildebrand’s early
career and
character.
We have now come to one of the real
crises of history. The new spirit had gained
ascendency at Rome, and the great man had
arisen who was to present the papal ideal with all the authority of
genius. Hildebrand of Soana[6]
was the son of a well-to-do Tuscan
peasant; he had been brought up by his uncle, abbot of the strict
convent of St. Mary’s on the Aventine, which was the centre of the
Cluniac ideas in Rome, and where he made his profession as monk.
He became the chaplain of Gregory VI. who, though he bought the
Papacy with gold, had striven his best to carry out the work of
reformation. When deprived of his office at Sutri, Gregory VI. had
been compelled to retire to Germany with the Emperor. Hildebrand,
now about twenty-five years old, accompanied his master in his exile.
In 1048 the deposed Pope died, and his chaplain betook himself to
Cluny, where he remained for a full year, and where, he tells us, he
would have gladly spent the rest of his life. But in 1049 Leo IX. passed
through Cluny on his way to Rome, and Hildebrand was commanded
to accompany him. With his return to Rome his active career began.
As papal sub-deacon he reorganised the crippled finances of the Holy
See, and strengthened the hold of the Pope over the unruly citizens.
As papal legate he was sent to France in 1054 to put down the heresy
of Berengar of Tours. But the death of Leo recalled him to Italy,
32. Stephen IX., 1057–
1058.
Nicholas II., 1058–
1061.
whence he went to the Emperor at the head of the deputation that
successfully requested the appointment of Victor II. With this Pope
he was as powerful as with Leo. But Victor II. died in 1057, and
Frederick of Lorraine left his newly-won abbot’s chair at Monte
Casino to ascend the throne of St. Peter as Stephen IX. Though a
zealot for the ideas of Cluny, Stephen, as the
head of the house of Lorraine, was the
natural leader of the political opposition to the imperial house both
in Germany and Italy. He made Peter Damiani a cardinal, and
zealously pushed forward the warfare against simony in Germany.
Stephen’s early death in 1058, when Hildebrand was away in
Germany, brought about a new crisis. The Counts of Tusculum
thought the moment opportune to make a desperate effort to win
back their old influence. They terrorised Rome with their troops, and
brought about the irregular election of one of the Crescentii, who
called himself Benedict X. The prompt action of Hildebrand
preserved the Papacy for the reforming party. He hurried back to
Florence, and formed a close alliance with Duke Godfrey of Lorraine,
Stephen’s brother, against the nominee of Tusculum. The stricter
cardinals met at Siena and chose Gerhard, Bishop of Florence, a
Burgundian by birth, as orthodox Pope. Gerhard held another synod
at Sutri, where the Antipope was formally deposed. Early in 1059 he
entered Rome in triumph. By assuming the
name of Nicholas II., he proclaimed himself
the successor of the most successful and aggressive of Popes. As
Archdeacon of Rome, Hildebrand acted as chief minister to the Pope
whom he had made. Henceforth till his death he dominated the
papal policy. While previous reformers had sought salvation by
calling the Emperor over the Alps, Hildebrand had found in Duke
Godfrey and his wife champions as effective for his purpose on
Italian soil. With the establishment of Pope Nicholas, through the
arms of Godfrey and Matilda, the imperial alliance ceases to become
a physical necessity to the reforming party in Italy. Hildebrand had
won for the Church her freedom. Before long he began to aim at
domination.
Nicholas II. ruled as Pope from 1058 to 1061. Within those few
years, three events were brought about which enormously
strengthened the position of the Papacy, already possessed of a great
moral force by its permanent identification with the reforming party,
33. Lateran Synod and
reform in Papal
elections, 1059.
The Normans
become the vassals
of the Pope, 1059.
and the final abasement of the unworthy local factions, that had so
long aspired to wield its resources. These events were the settlement
of the method of papal elections, the establishment of a close alliance
between the Papacy and the Normans of southern Italy, and the
subjection of Lombardy to the papal authority.
In 1059 Nicholas held a synod in the
Lateran which drew up the famous decree
that set aside the vague ancient rights of the
Roman clergy and people to choose their bishop, in favour of the
close corporation of the College of Cardinals. The decree was drawn
up in studiously vague language, but put the prerogative voice into
the very limited circle of the seven cardinal bishops of the
suburbicarian dioceses. These were to add to themselves the cardinal
priests and deacons, whose assent was regarded as including that of
clergy and people at large. A Roman clerk was to be preferred if
worthy, and Rome was to be the ordinary place of election; but, if
difficulties intervened, any person could be chosen, and any place
made the seat of election. The due rights of King Henry and his
successors to confirm their choice were reserved, but in terms that
suggested a special personal favour granted of his own goodwill by
the Pope to a crowned Emperor, rather than the recognition of an
immemorial legal right. The decree did not, as was hoped, save the
Church from schisms like those of Benedict X. Neither was the pre-
eminence of the suburbicarian bishops permanently maintained. But
henceforth the legal right of the cardinals to be the electors of future
Popes became substantially uncontested. It is not likely that this
involved any real change of practice. But in embodying custom in a
formal shape it gave subsequent efforts to set up Antipopes the
condemnation of illegality, and so stood the Papacy in good stead in
the troubles that were soon to ensue. The council also witnessed the
abject degradation of the Antipope and the recantation of the heretic
Berengar of Tours.
In the years that followed the battle of
Civitate, the Normans had steadily
extended their power over Apulia and
Calabria. But the south of Italy is so rugged and mountainous that
even the bravest of warriors could only win their way slowly. In 1057
the valiant Count Humphrey died, leaving his sons so young that he
34. Roger of
Hauteville.
Synod of Melfi.
Robert, Duke of
Apulia; and
Richard, Duke of
Capua.
had been constrained to beg his brother Robert to act as their
protector. But the barons of Apulia insisted that Robert should be
their count in full succession to Humphrey. Soon after Roger of
Hauteville, the youngest of the twelve sons of Tancred, left the
paternal roof to share the fortune of his brothers. ‘He was,’ says
Geoffrey of Malaterra, ‘a fine young man, of lofty stature and elegant
proportions. Very eloquent in speech, wise in counsel, and gifted
with extraordinary foresight, he was gay and affable to all, and so
strong and valiant that he soon gained the good graces of every one.’
Robert Guiscard received Roger in a more
brotherly spirit than had been shown on his
own first arrival by Drogo and Humphrey. He gave him a sufficient
following of troops and sent him to Calabria, where he soon
established himself as lord of half the district, though under his
brother’s overlordship. Meanwhile, Richard of Aversa had driven out
the Lombards from Capua and added it to his dominions. The
Normans were still, however, not free from danger from the Popes.
Victor II. had disapproved of Leo IX.’s policy, yet before his death he
had become their enemy. Stephen IX. formed various projects against
them. But Hildebrand now turned Nicholas II. to wiser counsels. In
1059 Hildebrand went in person to Capua and concluded a treaty
with Count Richard, who, as the ally of the monks of Monte Casino,
was the most friendly of the Norman chieftains to the Church.
Almost immediately the archdeacon returned to Rome with a strong
Norman escort, and soon after a Norman army spread terror among
the partisans of the Antipope. In the
summer of 1059 Nicholas himself held a
synod in Melfi, the Apulian capital, where he passed canons
condemning married priests. After the formal session was over, the
Pope made Robert Guiscard Duke of Apulia and Calabria, and ‘future
Duke’ of Sicily, if he should ever have the good luck to drive out the
infidels. In return Robert, ‘Duke by the
grace of God and of St. Peter,’ agreed to
hold his lands as the Pope’s vassal, paying
an annual rent of twelve pence for each
ploughland. Richard of Capua, either then or earlier, took the same
oath. Thus the famous alliance between the Normans and the Papacy
was consummated, which by uniting the strongest military power in
Italy to the papal policy, enabled the Holy See to wield the temporal
35. The Patarini in
Lombardy.
Milan submits to
Rome.
Alexander II. 1061–
1073.
with almost as much effect as the spiritual sword. Thus the Papacy
assumed a feudal suzerainty over southern Italy which outlasted the
Middle Ages. Within seven years of the Synod of Melfi, the
establishment of the Norman duke William the Bastard in England,
as the ally of the Pope, still further bound the most restless, active,
and enterprising race in Europe to the apostolic see.
The Pope now intervened decisively in
the long struggle between the traditional
and the strict parties in Lombardy, where the ancient independence
of the archbishops of Milan had long been assailed by the Patarini or
rag-pickers, as the reformers were contemptuously called. Lovers of
old ways in the north, with the Archbishop Guido of Milan at their
head, had long upheld clerical marriage as the ancient custom of the
Church of St. Ambrose. Peter Damiani was now sent as papal legate
to Milan to uphold the ‘rag-bags’ in their struggle. At a synod held in
Milan, the zealous monk made short work of the married clerks and
of the immemorial rights of the archbishop. Guido proffered an
abject submission and received a contemptuous restitution of his
archbishopric. The continuance of the friendship of Godfrey and
Matilda secured middle Italy, as the alliance with Normans and
Patarini had secured the south and the north. The strongest princes
of Gaul and Burgundy were on the zealots’
side. The imperialist prelates of Germany,
headed by Anno of Cologne, made a faint effort to stem the tide, but
the decrees fulminated by German synods against Nicholas and his
work were unknown or disregarded in Italy.
The untimely death of Nicholas in no wise
altered the course of events. The next Pope,
Alexander II., was Anselm, Bishop of Lucca, who had shared with
Peter Damiani in the victory over the simoniacs and married clerks
in Lombardy. His appointment by the cardinals without the least
reference to King Henry IV. gave the greatest offence in Germany,
and brought to a head the growing tension between Empire and
Papacy. A synod at Basel declared Pope Alexander’s election invalid,
and set up an Antipope, Cadalus, Bishop of Parma, who had been the
real soul of the opposition to the Patarini in Lombardy. Honorius II.
(this was the name he assumed) hurried over the Alps, and in 1062
was strong enough, with the help of the Counts of Tusculum, to fight
36. Later triumphs of
Robert Guiscard,
1068–1085.
an even battle with Alexander’s partisans, and for a time to get
possession of St. Peter’s. But the factions that controlled the
government of the young Henry IV. could not unite even in upholding
an Antipope, while the religious enthusiasm, which the reforming
movement had evoked, was ardently on the side of Alexander.
Condemned by Anno of Cologne and his party in Germany, Honorius
was rejected in 1064 by a council at Mantua. Nevertheless, he
managed to live unmolested and with some supporters until his own
death in 1072. His successful rival Alexander only outlived him a
year. It was then time for the archdeacon himself to assume the
responsible leadership of the movement which he had so long
controlled. In 1073 Hildebrand became Pope Gregory VII.
The reconciliation with the Papacy stood
the Normans in good stead. Henceforth
they posed as the champions of Western
Catholicism against Eastern Orthodoxy and Islam. Though the
Norman chieftains still wrangled hotly with each other, the tide in
south Italy had definitely turned in their favour. In 1071 the capture
of Bari, after a three years’ siege, finally expelled the Greeks from
Italy. The Lombard principality of Salerno was also absorbed, and
the greater part of the territories of the dukes of Benevento, save the
city and its neighbourhood, which Robert Guiscard, much to his own
disgust, was forced to yield to his papal suzerain. We shall see in
other chapters how Robert crossed the Straits of Otranto and aspired
to conquer the Greek Empire, how he came to the help of Gregory VII.
in his greatest need, and how his son Bohemund took part in the first
Crusade and founded the principality of Antioch. When Robert died
in 1085, all southern Italy acknowledged him as its lord, save the
rival Norman principality of Capua, the half-Greek republics of
Amalfi and Naples, and the papal possession of Benevento.
While Robert Guiscard was thus consolidating his power in the
peninsula, an even harder task was being accomplished by his
younger brother Roger, sometimes in alliance, and sometimes in
fierce hostility with the Duke of Apulia. The grant of Nicholas II. had
contemplated the extension of the Norman rule to Sicily. The
divisions of the Mohammedan world had cut off the island from the
Caliphate of the Fatimites, and its independent Ameers were hardly
equal to the task of ruling the island and keeping in order a timid but
37. Roger’s conquest of
Sicily, 1060–1101.
The feudalisation of
Naples and Sicily.
refractory population of Christian serfs. The
increasing power of Robert was fatal to the
independence of Roger in Calabria, and he gladly accepted the
invitation of the discontented Christians of Messina to deliver them
from the bondage of the infidel. In 1060 Roger led his first
expedition to Sicily, which was unsuccessful. But early next year he
came again, and this time the dissensions of the Mohammedans in
Sicily enabled him to have friends among Saracens as well as
Christians. In the summer of 1061 Robert came to his help. Messina
was easily captured, and proved invaluable as the starting-point of
later expeditions. The infidels were badly beaten at the battle of
Castrogiovanni, and before the end of the year the standards of
Roger had waved as far west as Girgenti. The first successes were not
quite followed up. In 1064 the Normans were forced to raise the
siege of Palermo. The compact Mussulman population of Western
Sicily opposed a very different sort of resistance to the invaders from
that which they had experienced in the Christian East. But the
process of conquest was resumed after the capture of Bari had given
Robert leisure to come to his brother’s help. In 1072 Palermo was
taken by the two brothers jointly. Robert claimed the lion’s share of
the spoil. Roger, forced to yield him the suzerainty of the whole
island, and a great domain under his direct rule, including Palermo
and Messina, threw himself with untiring zeal into the conquest of
the parts of the island that still adhered to Islam. Thirty years after
his first expedition, the last Saracens were expelled from the rocky
fastnesses of the western coasts, and the inaccessible uplands of the
interior. The Normans took with them to
Italy their language, their manners, their
art, and above all, their polity. On the ruins of the Greek, Lombard
and Saracen power, the Normans feudalised southern Italy so
thoroughly that the feudalism of Naples and Sicily long outlasted the
more indigenous feudalism of Tuscany or Romagna. Freed from his
grasping brother’s tutelage after 1085, Roger ruled over Sicily as
count till his death in 1101. We shall see how his son united Sicily
with Apulia in a single sovereignty, which has in various shapes
endured as the kingdom of Naples or Sicily, until the establishment
of a united Italy in our own days.
40. The minority of
Henry IV., 1056–
1072.
Regency of the
Empress Agnes,
1056–1062.
CHAPTER VI
THE INVESTITURE CONTEST (1056–1125)
Minority of Henry IV.—Regency of Agnes—Rivalry of Adalbert and
Anno—The Saxon Revolt—Election of Gregory VII.—Beginnings of
the Investiture Contest—Canossa and its results—Rudolf of
Swabia and Guibert of Ravenna—The Normans and Gregory VII.
—Victor III. and Urban II.—Last years of Henry IV.—Henry V. and
Pascal II.—Calixtus II. and the Concordat of Worms—Death of
Henry V.
While the Cluniac movement had at last attained ascendency over
the best minds of Europe, and a swarm of monastic reformers had
prepared the way for the great revival of spiritual religion and
hierarchical pretensions; while in Italy strong papalist powers, like
the Countess Matilda and the Normans of the south, had arisen to
menace the imperial authority, the long minority of Henry IV. sapped
the personal influence of Cæsar over Italy and brought about a
lengthened period of faction and weak rule in Germany. On Henry
III.’s death, his son, Henry IV., was a boy of
six. The great Emperor’s power secured the
child’s undisputed succession, but was too
personal, too military in its character to prove any safeguard against
the dangers of a long minority. Nor did the choice of ruler during
Henry IV.’s nonage improve the state of affairs. Henry III.’s widow,
Agnes of Poitou, a pious well-meaning lady, acted as regent for her
son, but her weakness of will and inconsistency of conduct gave full
scope to discontented nobles ready to take advantage of a woman’s
sway. The lay nobles availed themselves of
her helplessness to plunder and despoil the
41. Abduction of Henry
by Anno of Cologne,
1062.
Rivalry of Adalbert
of Bremen and
Anno of Cologne,
1065–1070.
prelates, while they complained that Agnes neglected their counsels
for those of low-born courtiers and personal favourites. After six
years of confusion the Empress was driven from power. Anno,
Archbishop of Cologne, a vigorous, experienced, and zealous prelate,
full of ambition and violence, joined himself with Otto of Nordheim,
the newly appointed Duke of Bavaria, Count Egbert of Brunswick,
and some of the bishops, in a well-contrived plot to get possession of
the young king. In May 1062 the three chief
conspirators visited the king at his palace of
Saint Suitbert’s, situated on an island in the
Rhine, some miles below Düsseldorf, now called Kaiserswerth. One
day after dinner Anno persuaded the boy king to inspect an
elaborately-fitted-up barge. As soon as Henry had entered the boat,
the oarsmen put off and rowed away. Henry was soon frightened and
plunged into the water, but Count Egbert leapt in and rescued him.
The king was pacified by flattery and taken to Cologne. The crowd
cried shame on the treachery of the bishop, but Henry remained in
his custody, and Agnes made no serious attempt to regain her
authority, but reconciled herself with Anno and retired into a
monastery. Anno proposed to the magnates that the regency should
be exercised by the bishop of the diocese in which the king happened
to be staying. By carefully selecting the king’s places of abode, he
thus secured the reality of power without its odium. By throwing over
the Antipope he procured the support of the Hildebrandine party,
and was likened by Peter Damiani to another Jehoiada. But his pride
and arrogance soon raised him up enemies; and young Henry, who
never forgave his abduction, bitterly resented his tutelage.
Adalbert, Archbishop of Bremen, took the
lead among Anno’s enemies. He was a man
of high birth, great experience, and
unbounded ambition, an old confidant of
Henry III., and filled with a great scheme for making his
archbishopric a permanent patriarchate over the infant churches of
Scandinavia. He made himself personally attractive to the king, who
contrasted his kindness and indulgence with the austerity of Anno.
By Adalbert’s influence Henry was declared of age to govern on
attaining his fifteenth year in 1065. Henceforth Adalbert disposed of
all the high offices in Church and State, and growing more greedy as
he became more successful, excited much ill-will among the religious
42. by plundering the monasteries right and left. He appropriated to
himself the two great abbeys of Lorsch and Corvey, and sought in
vain to propitiate his enemies by allowing other magnates, including
even his rival Anno, to similarly despoil other monasteries. The king
was made so poor that he hardly had enough to live on. But Adalbert
at least sought to continue the great traditions of statecraft of Henry
III., and showed more policy and skill than the crowd of bishops who
had previously shared power with Anno. At last, in 1066, the nobles
combined against Adalbert at a Diet at Tribur, and Henry was
roundly told that he must either dismiss Adalbert or resign his
throne. Adalbert retired to his diocese, and Anno and Otto of
Nordheim again had the chief control of affairs. But neither party
could rule with energy or spirit, and Henry, now nearly grown up,
showed no decided capacity to make things better. The young king
was tall, dignified, and handsome. He was affable and kindly to men
of low rank, with whom he was ever popular, though he could be
stern and haughty to the magnates, whose power he feared. He had
plenty of spirit and fair ability. But he had been brought up so laxly
by Archbishop Adalbert that he was headstrong, irresolute,
profligate, and utterly deficient in self-control. He never formulated
a policy, and if he championed great causes, he did so blindly and in
ignorance. Married to Bertha, daughter of the Marquis Odo of Turin,
in 1065, he gave offence both to her powerful kinsfolk and to the
strict churchmen by refusing to live with her, and talking of a
divorce. He had now to put down open rebellions. In 1069 the
Margrave Dedi strove to rouse the Thuringians to revolt, and in 1070
Otto of Bavaria, the most important of the dukes surviving, after the
death of Duke Godfrey of Lorraine in the previous year, was driven
into rebellion. So divided were the German nobles, so helpless the
German king, that instead of ruling the Italians, there seemed every
prospect of the Italians ruling them. In 1069 Peter Damiani went to
Germany as legate, and compelled Henry to reconcile himself with
Bertha. Peter was horrified at the unblushing simony of the German
bishops, and, on his report, Anno of Cologne and several other of the
greatest prelates of Germany were summoned to Rome and
thoroughly humiliated. Anno atoned for his laxity by his edifying
discharge of the meanest monastic duties in his own great
foundation at Siegburg, but his influence was gone and his political
career was at an end. His fall brought Adalbert back to some of his
43. The Saxon Revolt,
1073–1075.
ancient influence. The death of the Archbishop of Bremen in 1072
unloosed the last link that connected the new reign with the old
traditions.
Henry IV.’s reign now really began. A
thorough Swabian, his favourite ministers
were Swabians of no high degree, and he had no faith in the goodwill
or loyalty of the men of the north. He had kept vacant the Saxon
dukedom. On every hill-top of Saxony and Thuringia he built strong
castles, whose lawless garrisons plundered and outraged the
peasantry. There was ever fierce ill-will between northern and
southern Germany during the Middle Ages. The policy of the
southern Emperor soon filled the north with anger, and the Saxon
nobles prepared for armed resistance. In 1073 Henry fitted out an
expedition, whose professed destination was against the Poles. It was
believed in Saxony that his real object was to subdue the Saxons and
hand them over to the Swabians. Accordingly in the summer of 1073
a general Saxon revolt broke out, headed by the natural leaders of
Saxony both in Church and State, including the Archbishop of
Magdeburg, the deposed Duke Otto of Bavaria, and the fierce
Margrave Dedi, already an unsuccessful rebel. The insurgents
demanded the instant demolition of the castles, the dismissal of
Henry’s evil counsellors, and the restitution of their lands that he
had violently seized. On receiving no answer they shut up Henry in
the strong castle of Harzburg, whence he escaped with the utmost
difficulty to the friendly cloister of Hersfeld. In the course of the
summer the rebels destroyed many of the new castles. The levies
summoned for the Polish campaign refused to turn their arms
against the Saxons, and Henry saw himself powerless amidst the
general falling away. A meeting at Gerstungen, where Henry’s friends
strove to mediate with the rebels, led to a suggestion that the king
should be deposed. Only at Worms and in the Swabian cities did
Henry receive any real support. He gathered together a small army
and strove to fight a winter campaign against the Saxons, but failed
so completely that he was forced to accept their terms. However,
hostilities were renewed in 1075, when Henry won a considerable
victory at Hohenburg on the Unstrut, and forced the Saxons to make
an unconditional submission. Otto of Nordheim, the Archbishop of
Magdeburg, and the other leaders were imprisoned. On the ruins of
Saxon liberty Henry now aspired to build up a despotism.
44. Election of Gregory
VII. 1073.
His character and
policy.
Hildebrand was now Pope. During the
funeral service of Alexander II. at St. John’s
in the Lateran, a great shout arose from the multitude in the church
that Hildebrand should be their bishop. The cardinal, Hugh the
White, addressed the assembly. ‘You know, brethren,’ he said, ‘how,
since the time of Leo IX., Hildebrand has exalted the Roman Church,
and freed our city. We cannot find a better Pope than he. Indeed, we
cannot find his equal. Let us then elect him, who, having been
ordained in our church, is known to us all, and thoroughly approved
by us.’ There was the great shout in answer: ‘Saint Peter has chosen
Hildebrand to be Pope!’ Despite his resistance, Hildebrand was
dragged to the church of St. Peter ad Vincula, and immediately
enthroned. The cardinals had no mind to upset this irregular
election, strangely contrary though it was to the provisions of
Nicholas II. The German bishops, alarmed at Hildebrand’s reputation
for severity, urged the king to quash the appointment, but Henry
contented himself with sending to Rome to inquire into the
circumstances of the election. Hildebrand showed great moderation,
and actually postponed his consecration until Henry’s consent had
been obtained. This Henry had no wish to withhold. On 29th June
1073 Hildebrand was hallowed bishop. By assuming the name of
Gregory VII., he proclaimed to the world the invalidity of the
deposition of his old master at the Synod of Sutri.
The wonderful self-control which the new
Pope had shown so long did not desert him
in his new position. Physically, there was little to denote the mighty
mind within his puny body. He was of low stature, shortlegged and
corpulent. He spoke with a stammer, and his dull complexion was
only lighted up by his glittering eyes. He was not a man of much
learning or originality, and contributed little towards the theory of
the papal or sacerdotal power. But he was one of the greatest
practical men of the Middle Ages; and his single-minded wish to do
what was right betokened a dignity of moral nature that was rare
indeed in the eleventh century. His power over men’s minds was
enormous, even to their own despite. The fierce and fanatical Peter
Damiani called him his ‘holy Satan.’ ‘Thy will,’ said he, ‘has ever been
a command to me—evil but lawful. Would that I had always served
God and St. Peter as faithfully as I have served thee.’ Even as
archdeacon he assumed so great a state, and lived in such constant
45. intercourse with the world, that monastic zealots like Damiani were
scandalised, and some moderns have questioned (though
groundlessly) whether he was ever a professed monk at all.
Profoundly convinced of the truth of the Cluniac doctrines, he
showed a fierce and almost unscrupulous statecraft in realising them
that filled even Cluny with alarm. His ideal was to reform the world
by establishing a sort of universal monarchy for the Papacy. He saw
all round him that kings and princes were powerless for good, but
mighty for evil. He saw churchmen living greedy and corrupt lives for
want of higher direction and control. Looking at a world distraught
by feudal anarchy, his ambition was to restore the ‘peace of God,’
civilisation, and order, by submitting the Church to the Papacy, and
the world to the Church. ‘Human pride,’ he wrote, ‘has created the
power of kings; God’s mercy has created the power of bishops. The
Pope is the master of Emperors. He is rendered holy by the merits of
his predecessor, St. Peter. The Roman Church has never erred, and
Holy Scripture proves that it never can err. To resist it is to resist
God.’ For the next twelve years he strove with all his might to make
his power felt throughout Christendom. Sometimes his enthusiasm
caused him to advance claims that even his best friends would not
admit, as when William the Conqueror was constrained to repudiate
the Holy See’s claims of feudal sovereignty over England, which,
after similar pretensions had been recognised by the Normans in
Sicily, Gregory and his successors were prone to assert whenever
opportunity offered. The remotest parts of Europe felt the weight of
his influence. But the intense conviction of the righteousness of his
aims, that made compromise seem to him treason to the truth, did
something to detract from the success of his statecraft. He was too
absolute, too rigid, too obstinate, too extreme to play his part with
entire advantage to himself and his cause. Yet with all his defects
there is no grander figure in history.
Gregory realised the magnitude of his task, but he never shrank
from it. ‘I would that you knew,’ wrote he to the Abbot of Cluny, ‘the
anguish that assails my soul. The Church of the East has gone astray
from the Catholic faith. If I look to the west, the north, or the south, I
find but few bishops whose appointments and whose lives are in
accordance with the laws of the Church, or who govern God’s people
through love and not through worldly ambition. Among princes I
know not one who sets the honour of God before his own, or justice
46. The Synod of 1075,
and the attack on
Simony and Lay
Investiture.
The beginnings of
the Investiture
Contest, 1075.
before gain. If I did not hope that I could be of use to the Church, I
would not remain at Rome a day.’ From the very first he was beset on
every side with difficulties. Even the alliance with the Normans was
uncertain. Robert Guiscard, with his brother Roger, waged war
against Gregory’s faithful vassal, Richard of Capua; and Robert, who
threatened the papal possession of Benevento, went so far that he
incurred excommunication. Philip of France, ‘the worst of the tyrants
who enslaved the Church,’ had to be threatened with interdict. A
project to unite the Eastern with the Western Church broke down
lamentably. A contest with Henry IV. soon became inevitable. But
Gregory abated nothing of his high claims. In February 1075 he held
a synod at Rome, at which severe decrees against simony and the
marriage of clerks were issued. The practice
of lay investiture, by which secular princes
were wont to grant bishoprics and abbeys
by the conferring of spiritual symbols such
as the ring and staff, had long been regarded by the Cluniacs as the
most glaring of temporal aggressions against the spiritual power.
This practice was now sternly forbidden. ‘If any one,’ declared the
synod, ‘henceforth receive from the hand of any lay person a
bishopric or abbey, let him not be considered as abbot or bishop, and
let the favour of St. Peter and the gate of the Church be forbidden to
him. If an emperor, a king, a duke, a count, or any other lay person
presume to give investiture of any ecclesiastical dignity, let him be
excommunicated.’ This decree gave the signal for the great
Investiture Contest, and for the greater struggle of Papacy and
Empire that convulsed Europe, save during occasional breaks, for the
next two centuries.
Up to the issue of the decree as to investitures, the relation
between Gregory and Henry IV. had not been unfriendly. Henry had
admitted that he had not always respected the rights of the Church,
but had promised amendment for the future. But to give up
investitures would have been to change the
whole imperial system of government. He
was now freed, by his victory at Hohenburg,
from the Saxon revolt. The German bishops, afraid of the Pope’s
strictness, encouraged his resistance, and even in Italy he had many
partisans. The Patarini were driven out of Milan, and Henry scrupled
not to invest a new archbishop with the see of St. Ambrose. Even at
47. Council at Worms,
1076.
Vatican Synod,
1076.
Weakness of
Henry’s position in
Germany.
Rome, Gregory barely escaped assassination while celebrating mass.
In January 1076 Henry summoned a German council to Worms.
Strange and incredible crimes were freely
attributed to the Pope, and the majority of
the German bishops pronounced him deposed. Henry himself wrote
in strange terms to the Pope: ‘Henry, king not by usurpation but by
God’s grace, to Hildebrand, henceforth no pope but false monk,—
Christ has called us to our kingdom, while He has never called thee
to the priesthood. Thou hast attacked me, a consecrated king, who
cannot be judged but by God Himself. Condemned by our bishops
and by ourselves, come down from the place that thou hast usurped.
Let the see of St. Peter be held by another, who will not seek to cover
violence under the cloak of religion, and who will teach the
wholesome doctrine of St. Peter. I, Henry, king by the grace of God,
with all of my bishops, say unto thee—“Come down, come down.”’
In February 1076 Gregory held a great
synod in the Vatican, at which the Empress
Agnes was present, with a great multitude of Italian and French
bishops. A clerk from Parma named Roland delivered the king’s
letter to the Pope before the council. There was a great tumult, and
Roland would have atoned for his boldness with his life but for the
Pope’s personal intervention. Henry was now formally
excommunicated and deposed. ‘Blessed Peter,’ declared Gregory,
‘thou and the Mother of God and all the saints are witness that the
Roman Church has called upon me to govern it in my own despite.
As thy representative I have received from God the power to bind
and to loose in Heaven and on earth. For the honour and security of
thy Church, in the Name of God Almighty, I prohibit Henry the king,
son of Henry the Emperor, who has risen with unheard-of pride
against thy Church, from ruling Germany and Italy. I release all
Christians from the oaths of fealty they may have taken to him, and I
order that no one shall obey him.’
War was thus declared between Pope and
king. Though the position of both parties
was sufficiently precarious, Henry was at
the moment in the worst position for carrying on an internecine
combat. He could count very little on the support of his German
subjects. Those who most feared the Pope were the self-seekers and
48. Diet of Tribur,
1076.
Humiliation of
Henry.
Henry’s winter
journey through
the simoniacs, whose energy was small and whose loyalty less. The
saints and the zealots were all against him. The Saxons profited by
his embarrassments to renew their revolt, and soon chased his
garrisons out of their land. The secular nobles, who saw in his policy
the beginnings of an attempt at despotism, held aloof from his court.
It was to no purpose that Henry answered the anathemas of Gregory
with denunciations equally unmeasured, and complained that
Gregory had striven to unite in his hands both the spiritual and the
temporal swords, that God had kept asunder. Hermann, Bishop of
Metz, the Pope’s legate in Germany, ably united the forces against
him. At last, the nobles and bishops of Germany gathered together
on 16th October 1076 at Tribur, where the papal legates were treated
with marked deference, though Henry took up his quarters at
Oppenheim, on the other bank of the Rhine, afraid to trust himself
amidst his disaffected subjects. Henry soon
saw that he had no alternative but
submission. The magnates were so suspicious of him that it needed
the personal intercession of Hugh, Abbot of Cluny, to prevail upon
them to make terms with him at all. Finally a provisional agreement
was patched up, upon conditions excessively humiliating to Henry.
The barons refused to obey him until he had
obtained absolution from the Pope, who,
moreover, had promised to go to Germany in person and hold a
council in the succeeding February. Pending this, Henry was to
remain at Speyer without kingly revenue, power, or dignity, and still
shut off by his excommunication from the offices of the Church. If
Henry could not satisfy the Pope in February, he was to be regarded
as deposed.
Abandoned by Germany, Henry abode some two months at
Speyer, gloomily anticipating the certain ruin to his cause that would
follow the Pope’s appearance in a German council. He realised that
he could do nothing unless he reconciled himself to Gregory; and,
hearing good news of his prospects in northern Italy, thought that his
best course was to betake himself over the Alps, where the Pope
might well prove less rigorous, if he found him at the head of a
formidable band of Italian partisans. It was a winter of extraordinary
severity, but any risks were better than inglorious inaction at Speyer.
Accordingly Henry broke his compact with
his nobles, and towards the end of
49. Burgundy and
Lombardy, 1076–
77.
Canossa, Jan.
1077.
December secretly set out on his journey
southward. He was accompanied by Bertha
and his little son, but only one German
noble was included among his scanty following. He traversed
Burgundy, and kept his miserable Christmas feast at Besançon.
Thence crossing the Mont Cenis at the risk of his life, he appeared
early in the new year amidst his Lombard partisans at Pavia. But
though urged to take up arms, Henry feared the risks of a new and
doubtful struggle. Germany could only be won back by submission.
He resolved to seek out the Pope and throw himself on his mercy.
Gregory was then some fifteen miles south of Reggio, at an
impregnable mountain stronghold belonging to the Countess
Matilda, called Canossa, which crowned one of the northern spurs of
the Apennines, and overlooked the great plain. He had sought the
protection of its walls as a safe refuge
against the threatened Lombard attack
which Henry, it was believed, had come over the Alps to arrange. The
Countess Matilda and Hugh of Cluny, Henry’s godfather, were with
the Pope, and many of the simoniac bishops of Germany had already
gone to Canossa and won absolution by submission. On 21st January
1077 Henry left his wife and followers at Reggio, and climbed the
steep snow-clad road that led to the mountain fastness. Gregory
refused to receive him, but he had interviews with Matilda and his
godfather in a chapel at the foot of the castle-rock, and induced them
to intercede with the Pope on his behalf. Gregory would hear of
nothing but complete and unconditional submission. ‘If he be truly
penitent, let him surrender his crown and insignia of royalty into our
hands, and confess himself unworthy of the name and honour of
king.’ But the pressure of the countess and abbot at last prevailed
upon him to be content with abject contrition without actual
abandonment of his royal state. For three days Henry waited in the
snow outside the inner gate of the castle-yard, barefoot, fasting, and
in the garb of a penitent. On the fourth day the Pope consented to
admit him into his presence. With the cry ‘Holy father, spare me!’ the
king threw himself at the Pope’s feet. Gregory raised him up,
absolved him, entertained him at his table, and sent him away with
much good advice and his blessing. But the terms of Henry’s
reconciliation were sufficiently hard. He was to promise to submit
himself to the judgment of the German magnates, presided over by
50. Results of Canossa.
Diet of Forchheim,
March 1077.
Rudolf of Swabia,
Anti-Cæsar.
the Pope, with respect to the long catalogue of charges brought
against him. Until that was done he was to abstain from the royal
insignia and the royal functions. He was to be prepared to accept or
retain his crown according to the judgment of the Pope as to his guilt
or innocence. He was, if proved innocent, to obey the Pope in all
things pertaining to the Church. If he broke any of these conditions,
another king was to be forthwith elected.
The humiliation of Henry at Canossa is so
dramatic and so famous an event that it is
hard to realise that it was but an incident in the midst of a long
struggle. It settled nothing, and profited neither Henry nor Gregory.
Gregory found that his harshness had to some extent alienated that
public opinion on which the Papacy depended almost entirely for its
influence. Henry found that his submission had not won over his
German enemies, but had thoroughly disgusted the anti-papal party
in northern Italy, upon which alone he could count for armed
support. The Lombards now talked of deposing the cowardly
monarch in favour of his little son. But the future course of events
rested after all upon the action of the German nobles, who held their
Diet at Forchheim in March 1077. To this
assembly Henry was not even invited; and
for the present he preferred remaining in Italy. The Pope also did not
appear in person, but was represented by two legates. The old
charges against Henry were brought up once more, and the legates
expressed their wonder that the patient Germans had submitted so
long to be ruled by such a monster. Without giving Henry the least
opportunity of refuting the accusations, it was determined to proceed
at once to the choice of a new king. The suffrages of the magnates fell
on Duke Rudolf of Swabia. Before his
appointment, Rudolf was compelled to
renounce all hereditary claim to the throne on behalf of his heirs, and
to allow freedom of election to all bishoprics. He was then crowned
at Mainz by Archbishop Siegfried.
The news of Rudolf’s election at once brought Henry back over the
Alps. He soon found that he now had devoted partisans in the land
that had rejected him when he was under the ban of the Pope. He
was warmly welcomed in Bavaria, in Burgundy, and especially in the
great towns of the Rhineland, always faithful to the imperial cause.
51. Civil war between
Rudolf and Henry,
1077–1080.
Battle of
Flarchheim, 1080.
Renewed
excommunication
and deposition of
Henry, March
1080.
Guibert of Ravenna
elected Antipope,
June 1080.
Rudolf’s own duchy of Swabia rejected its
duke in favour of the prince who had ever
loved the Swabians. Rebel Saxony was alone
strongly on Rudolf’s side. Even the Pope could not make up his mind
to ratify the action of his legates and accept Rudolf as king. For more
than two years civil war raged between Rudolf and Henry. It was
substantially a continuation of the Saxon revolt. At last, in January
1080, a decisive battle was fought at Flarchheim on the banks of the
Unstrut, in which Henry was utterly defeated. During all this time
Gregory had contented himself with offers
of arbitration. Though Henry practised lay
investiture as freely as ever, it was not until after his defeat that the
Pope once more declared himself against him. Yielding to the
indignant remonstrances of Rudolf and the Saxons, he convoked a
synod at Rome in March 1080, where he renewed Henry’s
excommunication, and again deprived him of his kingdoms of
Germany and Italy. ‘Act so,’ said Gregory to
the assembled prelates, ‘that the world shall
know that ye who have power to bind and to
loose in heaven, can grant or withhold
kingdoms, principalities, and other
possessions according to each man’s merits. And if you are fit to
judge in things spiritual, ought ye not to be deemed competent to
judge in things temporal?’ Rudolf was now recognised as king, and
another universal prohibition of lay investitures was issued.
Gregory boasted that, before the next feast of SS. Peter and Paul,
Henry would have lost his throne and his life. But each fresh
aggression of the Pope increased his rival’s power. Henry now
showed an energy and vigour that contrasted strangely with his
spiritless action three years before. Both in Germany and Italy he
found himself supported by partisans as enthusiastic as those of the
Pope. The bishops of Germany declared for him, and the old foes of
the Pope in Italy took courage to continue the contest. In June Henry
met at Brixen the German and Italian
bishops who adhered to his side. This
assembly declared Gregory deposed and
excommunicate, and elected Guibert, Archbishop of Ravenna as his
successor.
52. Battle on the Elster,
and death of
Rudolf, 15th
October 1080.
Hermann of
Luxemburg, Anti-
Cæsar.
Henry’s visit to
Italy, 1081.
War between
Henry and Gregory,
1081–1084.
The new Antipope had in his youth served Henry III., and, as
chancellor of Italy, had striven to uphold the imperial authority
during Henry IV.’s minority. He had once been on friendly terms with
Gregory, but had quarrelled with him, and had for some time been
the soul of the imperialist party in north Italy. He was of high birth,
unblemished character, great abilities, and long experience. He
assumed the title of Clement III., and at once returned to Ravenna to
push matters to extremities against Gregory. The rash violence of the
Pope had been answered with equal violence by his enemies. There
were two Popes and two Emperors. The sword alone could decide
between them.
Fortune favoured Henry and Clement
both in Germany and Italy. On 15th October
1080 a great battle was fought on the banks
of the Elster, not far from the later
battlefields of Lützen. The fierce assault of Otto of Nordheim
changed what threatened to be a Saxon defeat into a brilliant victory
for the northern army. But Rudolf of Swabia was slain, and the
victorious Saxons wasted their opportunity while they quarrelled as
to his successor. It was nearly a year before they could agree upon
Hermann of Luxemburg as their new king.
Before this the back of the revolt had been
broken, and Henry, secure of Germany, had
once more gone to Italy. Crossing the Brenner in March 1081, he
went on progress through the Lombard cities, and abode with Pope
Clement at Ravenna. Thence he set out for Rome, meeting little
resistance on his way save from the Countess Matilda. The Normans
of Naples, on whose help Gregory had
counted, made no effort to protect their
suzerain. In May Henry celebrated the Whitsun feast outside the
walls of Rome.
Gregory did not lose his courage even with the enemy at his gate.
The Romans were faithful to him, and Henry, who saw no chance of
besieging the great city successfully, was forced to retreat northwards
by the feverish heat of summer. He retired
to Lombardy, where his position was
unassailable. Next year he was back again
before the walls of Rome, but the occupation of Tivoli was his
53. Coronation of
Henry by Guibert,
1084.
The Normans come
to Gregory’s help,
1084.
Sack of Rome.
Death of Gregory in
exile, 1085.
greatest success. In 1083 a third attack gave him possession of the
Leonine city, but even in this extremity Gregory would listen to no
talk of conciliation. ‘Let the king lay down his crown and make
atonement to the Church,’ was his answer to those who besought him
to come to terms. In the early months of 1084 Henry invaded Apulia
and kept in check the Normans, who at last were making a show of
helping the Pope. In March he appeared for the fourth time before
Rome. This time the Romans opened their gates, and Gregory was
closely besieged in the castle of St. Angelo.
A synod was hastily summoned, which
renewed his deposition and
excommunication. On Palm Sunday, 1084, Guibert was enthroned,
and on Easter Day he crowned Henry Emperor at St. Peter’s.
Gregory sent from the castle of St. Angelo
an urgent appeal for help to Robert
Guiscard. During the troubles of the last few
years, Robert’s obligations to his suzerain had weighed very lightly
upon him, but Henry’s invasion of Apulia and the certain ruin of the
Normans in Naples if the Pope succumbed, at last brought him to
decided action. Hastily abandoning his Greek campaign, Robert
crossed over to Italy, and in May advanced to the walls of Rome with
a large and motley army, in which the Saracens of Sicily were a
prominent element. Henry, who had no force sufficient to resist,
quitted Rome, and soon crossed the Alps. The Romans tried in vain
to defend their city from the Normans. After a four days’ siege
treason opened the gates. Rome was
ruthlessly sacked, whole quarters were
burned down, hideous massacres and outrages were perpetrated,
and thousands of Romans were sold as slaves. The Normans then
marched home. Gregory could not remain in the desolate city, and
followed them to Salerno. The Antipope kept his Christmas amid the
ruins of Rome, but soon abandoned the city for his old home at
Ravenna. Gregory now fell sick at Salerno. The few faithful cardinals
strove to console him by dwelling on the great work which he had
accomplished. ‘I set no store by what I have
done,’ was his answer. ‘One thing only fills
me with hope. I have always loved the law of God and hated iniquity.
Therefore I die in exile.’ He passed away on 25th May 1085. Less
than two months afterwards, Robert Guiscard died at Corfu.
54. Victor III., 1086–
1087.
Urban II., 1088–
1099.
Henry revisits Italy,
1090.
For a year after Gregory’s death, the Papacy remained vacant. At
last, in May 1086, the cardinals, profiting by the Antipope’s return to
Ravenna, met at Rome and forced the Papacy on the unwilling
Desiderius, Abbot of Monte Casino. The new Pope (who assumed the
name of Victor III.), was a close friend of Gregory’s and strongly
attached to his ideals. But he was too old
and too weak to take up Hildebrand’s task,
and three days after his election he strove to avoid the troublesome
dignity by flight to Monte Casino. Next year he was with difficulty
prevailed upon to return to Rome to receive the tiara. But the
partisans of the Emperor and of the Countess Matilda fought fiercely
for the possession of Rome, and Victor again retreated to his
monastery, where death ended his troubles three days after his
return (16th September 1087). Next time the cardinals fixed upon a
Pope of sterner stuff. Driven from Rome by the Antipope, they made
their election at Terracina on 12th March 1088. Their choice fell
upon the son of a baron of Champagne named Odo, who had lived
long at Cluny as monk and sub-prior, and then served the Roman
Court as cardinal-bishop of Ostia. Urban II.
(this was the title he took) was a man of
ability and force of character, as ardent as Hildebrand for the Cluniac
ideals, but more careful of his means of enforcing them than the
uncompromising Gregory. He made closer his alliance with the
Normans, and, thanks to the help of Duke Roger, Robert Guiscard’s
son and successor, was able to return to Rome and remain there for
some months. But the troops of the Antipope still held the castle of
St. Angelo, and Urban soon found it prudent to retire. He mainly
spent the first years of his pontificate in southern Italy under Roger’s
protection.
Meanwhile, papalists and imperialists fought hard in northern
Italy. Germany was now tolerably quiet, and Henry could now devote
his chief energies to Italy, which he revisited in 1090. But Urban
united the German with the Italian
opposition to the Emperor by bringing
about a politic marriage between the Countess Matilda and the
young son of Welf or Guelf, Duke of Bavaria, the Emperor’s most
powerful adversary in Germany. Despite this combination, Henry’s
Italian campaigns between 1090 and 1092 were extraordinarily
successful. Matilda’s dominions in the plain country were overrun,
55. Conrad of
Franconia, Anti-
Cæsar, 1093.
Urban’s Councils at
Piacenza and
Clermont, 1095.
The proclamation
of the First Crusade,
1095.
and her towns and castles captured. But she held her own in her
strongholds in the Apennines, rejected all compromise, and prepared
to fight to the last. Henry met his first check when he was driven
back in disgrace from an attempted siege of Canossa.
The papalists were much encouraged by
Henry’s defeat. Soon after they persuaded
his son Conrad, a weak and headstrong
youth, to rise in revolt against his father. Half Lombardy fell away
from father to son. Before the year was out, Conrad received the Iron
Crown at Milan, and Urban ventured back to Rome. Worse was to
follow. Henry’s second wife, Praxedis of Russia (Bertha had died in
1087), escaped from the prison to which her husband had consigned
her, and taking refuge with the Countess Matilda, gave to the world a
story of wrongs and outrages that destroyed the last shreds of the
Emperor’s reputation. In high glee at the progress of his cause,
Urban set out on a lengthened progress that reminds us of the
memorable tours of Leo IX. After a long stay
in Tuscany, he crossed the Apennines early
in 1095, and held a great synod at Piacenza,
at which the laws against simony and married clerks were renewed,
while the Empress publicly declared her charges against Henry, and
ambassadors from the Eastern Emperor pleaded for help, against the
growing power of the Seljukian Turks. In the summer Urban crossed
the Alps, and remained for more than a year in France and
Burgundy, being everywhere received with extraordinary reverence.
In November 1095 he held a largely attended synod at Clermont in
Auvergne. Not content with his quarrel with the Emperor, he here
fulminated excommunication against Philip I. of France, on account
of his adultery with Bertrada, Countess of Anjou. But the famous
work of the Council of Clermont was the proclamation of the First
Crusade. Nothing shows more clearly the
strength and nature of the papal power than
that this greatest result of the universal
monarchy of the Church should have been brought about at a time
when all the chief kings of Europe were open enemies of the Papacy.
Henry IV. was an old foe, Philip of France had been deliberately
attacked, and William Rufus of England was indifferent or hostile.
But in the eleventh century the power of even the strongest kings
counted for very little. What made the success of Urban’s endeavour
56. Urban’s return to
Italy, 1096.
Henry abandons
Italy, 1097.
Urban II. in
southern Italy,
1098.
Synod at Bari.
was the appeal to the swarm of small feudal chieftains, who really
governed Europe, and to the fierce and undisciplined enthusiasm of
the common people, with whom the ultimate strength of the Church
really lay.
Flushed with his success at Clermont,
Urban recrossed the Alps in September
1096. Bands of Crusaders, hastening to the East, mingled with the
papal train as he again traversed northern Italy. Rome itself now
opened its gates to the homeless lord of the Church. In 1097 Henry
IV. abandoned Italy in despair. He restored
the elder Welf to the Bavarian duchy, and
easily persuaded the younger Welf to quit his elderly bride, and
resume his allegiance to the Emperor. Conrad was deprived of the
succession, and his younger brother Henry crowned king at Aachen
on taking an oath that he would not presume to exercise royal power
while his father was alive.
Urban was now triumphant, save that his
Norman allies were once more giving him
trouble, and the castle of St. Angelo was still
held for the Antipope. He accordingly again visited southern Italy,
and won over Count Roger of Sicily, by conceding the famous
privilege to Roger and his heirs that no papal legate should be sent
into their lands without their consent, but that the lords of Sicily
should themselves act as legates within their dominions. In October
1098 the Pope held a synod at Bari, restored
to Catholicism by the Norman conquest in
1071. There, with a view to facilitating the Crusade, the great point of
difference between the Eastern and Western Churches—the
Procession of the Holy Ghost—was debated at length. Among the
prelates attending the council was Anselm of Canterbury, exiled for
upholding against William Rufus the principles which Urban had
asserted against the Emperor and the King of France. Urban, who
had been politic enough not to raise up a third great king against him
by supporting Anselm, atoned for past neglect by the deference he
now showed to the ‘Pope of the second world.’ As the council broke
up, the good news came that the castle of St. Angelo had at last been
captured. Urban returned to Rome and devoted himself to the work
of the Crusade. On 29th July 1099 he died suddenly. It was his glory
57. Death of Urban II.,
1099.
Death of Conrad,
1101.
Paschal II., 1099–
1118.
Revolt of the young
King Henry, 1104.
that the struggle of Pope and Emperor, which had absorbed all the
energies of Gregory VII., sank during his pontificate into a second
place. Though he abandoned no claim that
Gregory had made, he had the good fortune
to be able to put himself at the head of crusading Europe, while his
opponent shrank into powerless contempt. Next year the Antipope
followed Urban to the grave. With Clement, the schism as a real force
died. Three short-lived Antipopes pretended to carry on his
succession until the death of the Emperor, but no one took them
seriously. With the flight of the last pretender in 1106, formal
ecclesiastical unity was again restored.
Driven out of Italy by his rebel son, Henry IV. found Germany
equally indisposed to obey him. Both north and south of the Alps, the
real gainers in the long struggle had been the feudal chieftains, and
Germany, like Italy, was ceasing to be a single state at all. In 1101 the
rebellious Conrad died at Florence, bitterly
regretting his treason. Henry’s main object
now was to restore peace to Germany, and to effect a reconciliation
with the Church. But the new Pope, Paschal
II. (Rainerius of Bieda, near Viterbo, elected
August 1099), renewed his excommunication, and was as unbending
as his predecessors. Before long Paschal was able to extend his
intrigues into Germany, and in 1104 the young King Henry raised the
Saxons in revolt against his father, and was recognised as king by the
Pope. But the Emperor had no spirit left for
a fresh contest. At Coblenz he threw himself
at his son’s feet, begging only that his own child should not be the
instrument of God’s vengeance on his sins. The young king asked for
forgiveness, and promised to give up his claims when his father was
reconciled with the Church. The Emperor trustfully disbanded his
soldiers, and was promptly shut up in prison by his twice-perjured
son. On 31st December 1105 he formally abdicated at Ingelheim, and
abjectly confessed his offences against the Church. He was told that
absolution could only come from the Pope in person, and that it was
a boon that he was allowed his personal freedom. He fled from
Ingelheim to Cologne, where the goodwill of the citizens showed him
that he still had friends. From Cologne he went to Aachen, and from
thence to Liége, whose bishop, Otbert, supported him. The Duke of
Lorraine declared himself for him, and help was expected from
58. Death of Henry IV.
1106.
Henry V., 1106–
1125.
Philip of France and Robert of Flanders. Henry now declared that his
abdication was forced on him, but offered any terms, compatible
with the possession of the throne, to get absolution from the Pope.
But on 7th August 1106 he died at Liége,
before the real struggle between him and
his son was renewed. The enmity of the Church grudged rest even to
his dead body. The Bishop of Speyer refused to allow the corpse of
the excommunicate to repose beside his ancestors in the stately
church which he himself had built, and for five years it lay in an
unconsecrated chapel.
On 5th January 1106 Henry V. was
crowned for the second time at Mainz. The
first months of his reign were disturbed by his father’s attempt to
regain power. When he was at last undisputed King of Germany, he
found that his cold-blooded treachery had profited him very little.
The Investiture Contest was still unsettled. Between 1103 and 1107
Anselm of Canterbury, restored to his see by William Rufus’ death,
had been carrying on a counterpart of the contest with Henry I. of
England. But the personal animosities which had embittered the
continental struggle were absent, and the dispute did not, as abroad,
involve the larger questions of the whole relations of Church and
State. It was easy, therefore, to settle it by a satisfactory compromise.
Yet at the very moment when Henry had agreed to lay aside
investiture with ring and staff, the envoys of Henry V. were informing
Paschal that their master proposed to insist upon his traditional
rights in the matter. The result was that the continental strife was
renewed with all its old bitterness.
For two years Henry was engaged in wars against Hungary and
Bohemia. In 1110 he resolved to visit Italy to receive the imperial
crown, and to re-establish the old rights of the Empire. Besides a
numerous army, he took with him ‘men of letters able to give reasons
to all comers’ for his acts, among whom was an Irish or Welsh monk
named David, who wrote, at his command, a popular account of how
the king had gone to Rome to extract a blessing from the Pope, as
Jacob had extorted the angel’s blessing.[7]
He found Italy too divided
to offer effectual resistance. The Countess Matilda was old, and
Paschal was no great statesman like Gregory or Urban. Early in 1111
the king’s army approached Rome. The Pope, finding that neither the
59. Henry’s Roman
journey. Paschal
renounces the
Temporalities of the
Church, 1111.
Tumult at Henry’s
Coronation.
Triumph of Henry
over Paschal.
Romans nor the Normans would help him,
sent to Sutri to make terms. Even in his
supreme distress he would not give up
freedom of elections or abate his hostility to
lay investitures; but he offered that if the
king would accept those cardinal conditions he would renounce for
the Church all its feudal and secular property. It was a bold or rash
attempt to save the spiritual rights of the Church by abandoning its
temporalities, lands, and jurisdictions. Henry naturally accepted an
offer which put the whole landed estates of the Church at his
disposal, and reduced churchmen to live on tithes and offerings—
their spiritual sources of revenue. Only the temporalities of the
Roman see were to be excepted from this sweeping surrender.
On Sunday, 12th February, St. Peter’s
church was crowded to witness the
hallowing of the Emperor by the Pope. Before the ceremony began
the compact was read, and the Pope renounced in the plainest
language all intervention in secular affairs, as incompatible with the
spiritual character of the clergy. A violent tumult at once arose.
German and Italian bishops united to protest vigorously against the
light-heartedness with which the Pope gave away their property and
jurisdictions, while carefully safeguarding his own. The congregation
dissolved into a brawling throng. The clergy were maltreated, and the
sacred vessels stolen. The coronation was impossible. The king laid
violent hands on Pope and cardinals, and the mob in the streets
murdered any Germans whom they happened to come across. After
three days of wild turmoil, Henry quitted the city, taking his
prisoners with him. After a short captivity, Paschal stooped to obtain
his liberty by allowing Henry to exercise investitures and appoint
bishops at his will. ‘For the peace and liberty of the Church,’ was his
halting excuse, ‘I am compelled to do what I would never have done
to save my own life.’ In return Henry promised to be a faithful son of
the Church. On 13th April Paschal crowned Henry with maimed rites
and little ceremony at St. Peter’s. Canossa was at last revenged.
Henry returned in triumph over the Alps, and solemnly interred his
father’s remains in holy ground at Speyer.
Henry’s triumph made a deep impression
on Europe. The blundering Pope had
60. Paschal repudiates
his concessions.
Conspiracies
against Henry in
Germany.
Death of the
Countess Matilda,
1115, and of Paschal
II., 1118.
betrayed the temporal possessions of the clergy, and the necessary
bulwarks of the freedom of the spiritual power. The event showed
that there were practical limits even to papal infallibility. Paschal was
as powerless to retreat from the position of Hildebrand, as he had
been to renounce the lands of all prelates but himself. The clergy
would not accept the papal decision. In France a movement to
declare the Pope a heretic was only stayed by the canonist Ivo of
Chartres declaring that the Pope, having acted under compulsion,
was not bound to keep his promise. The Italians gladly accepted this
way out of the difficulty. Paschal solemnly
repudiated his compact. ‘I accept,’ he
declared, ‘the decrees of my master, Pope Gregory, and of Urban of
blessed memory; that which they have applauded I applaud, that
which they have granted I grant, that which they have condemned I
condemn.’
Even in Germany Henry found that he had gained nothing by his
degradation of the Pope. The air was thick with plots and
conspiracies. His most trusted councillors became leaders of treason.
Adalbert, Archbishop of Mainz, his chief
minister, formed a plot against him and was
imprisoned. The Saxons rose once more in
revolt under their new Duke Lothair of Supplinburg. Friesland
refused to pay tribute. Cologne rose under its Archbishop, and Henry
found that he was quite unable to besiege it successfully. The nobles
who attended his wedding with Matilda of England at Mainz,
profited by the meeting to weave new plots. Next year the citizens of
Mainz shut up the Emperor in his palace while he was holding a Diet,
and forced him to release their Archbishop.
Affairs in Italy were even more gloomy.
In 1115 the Countess Matilda died, leaving
all her vast possessions to the Holy See. If
this will had been carried out, Paschal
would have become the greatest temporal power in Italy. Henry
therefore crossed the Alps in 1116, anxious, if not to save Matilda’s
allodial lands, to take possession of the fiefs of the Empire which she
had held. In 1117 Henry occupied Rome and crowned his young
English wife Matilda. Even in his exile Paschal had not learnt the
61. Gelasius II. (1118–
1119).
The Antipope
Burdinus.
Calixtus II. (1119–
1124).
Negotiations for a
settlement.
lesson of firmness. He died early in 1118, before he had even
definitely made up his mind to excommunicate Henry.
The new Pope, John of Gaeta, a monk of
Monte Casino, who took the name of
Gelasius II., was forced to flee from Rome as the Emperor was
entering it. Henry now took the decisive step of appointing a Pope of
his own. Burdinus, Archbishop of Braga, was in some fashion chosen
by a few cardinals, and took the name of Gregory VIII. Gelasius at
once excommunicated both Antipope and
Emperor. He soon managed to get back to
Rome, whence, however, he was again expelled by the malignity of
local faction rather than the influence of the Emperor. He now
betook himself to Marseilles by sea, and, after a triumphant progress
through Provence and Burgundy, held a synod at Vienne. On his way
thence to Cluny he was smitten with pleurisy, reaching the
monastery with difficulty, and dying there on 18th January 1119.
Guy, the high-born Archbishop of Vienne, was chosen somewhat
irregularly by the cardinals who had followed Gelasius to Cluny. He
had long been conspicuous as one of the ablest upholders of
Hildebrandine ideas in the dark days of Paschal II. The son of
William the Great, Count of imperial
Burgundy (Franche-Comté), he was the
kinsman of half the sovereigns of Europe. He was, moreover, a
secular (the first Pope not a monk since Alexander II.), and
accustomed to diplomacy and statecraft. He resolved to make an
effort to heal the investiture strife, and with that object summoned a
council to meet at Reims. Henry himself
was tired of the struggle. He practically
dropped his Antipope, and gave a patient hearing to the agents of the
Pope, who came to meet him at Strasburg. These were Hugh, Abbot
of Cluny, and the famous theologian, William of Champeaux, now
Bishop of Châlons. The two divines pointed out to Henry that the
King of France, who did not employ investiture, had as complete a
hold over his bishops as the Emperor, and that his father-in-law,
Henry of England, who had yielded the point, was still lord over his
feudal vassals, whether clerks or laymen. For the first time perhaps,
the subject was discussed between the two parties in a reasonable
and conciliatory spirit. Before the king and the divines parted, it was
62. Welcome to our website – the ideal destination for book lovers and
knowledge seekers. With a mission to inspire endlessly, we offer a
vast collection of books, ranging from classic literary works to
specialized publications, self-development books, and children's
literature. Each book is a new journey of discovery, expanding
knowledge and enriching the soul of the reade
Our website is not just a platform for buying books, but a bridge
connecting readers to the timeless values of culture and wisdom. With
an elegant, user-friendly interface and an intelligent search system,
we are committed to providing a quick and convenient shopping
experience. Additionally, our special promotions and home delivery
services ensure that you save time and fully enjoy the joy of reading.
Let us accompany you on the journey of exploring knowledge and
personal growth!
ebookfinal.com