This document provides an overview of three major movements in early modern architecture: De Stijl, Constructivism, and the Bauhaus. It describes the origins and key principles of each movement. De Stijl emerged in the Netherlands in 1915 and was influenced by Mondrian's paintings using primary colors and horizontal and vertical lines. Constructivism developed in Russia in the 1920s and emphasized abstraction, experimentation with geometry and industrial materials. The Bauhaus school operated in Germany from 1919-1933 under directors including Gropius and Mies van der Rohe, combining crafts and technology to create standardized designs emphasizing function over ornament.