After the fall of the Western Roman Empire, Europe entered a period of decline known as the Middle Ages. Three groups contributed to the emergence of a new civilization: the Romans through their legacy of laws and infrastructure; the Christian Church which spread across Europe and established a hierarchical organization; and Germanic tribes which established new kingdoms and introduced concepts of loyalty and family. Charlemagne later united much of Western Europe under the Carolingian Empire and was crowned by the Pope, representing the fusion of Roman, Christian and Germanic influences. However, his empire did not endure and Europe remained politically fragmented.