DIVERGENCE OF EAST AND WEST Before the Christian conquest of Europe was finished, Christianity had divided into two great communions--the Greek Church and the Roman Church. Their separation was a long, slow process, arising from the deep-seated differences between East and West. Though Rome had carried her conquering arms throughout the Mediterranean basin, all the region east of the Adriatic was imperfectly Romanized. [30] It remained Greek in language and culture, and tended, as time went on, to grow more and more unlike the West, which was truly Roman. The founding of Constantinople and the transference of the capital from the banks of the Tiber to the shores of the Bosporus still further widened the breach between the two halves of the Roman world. After the Germans established their kingdoms in Italy, Spain, Gaul, and Britain, western Europe was practically independent of the rulers at Constantinople. The coronation of Charlemagne in 800 A.D. marked the final severance of East and West. THE PAPACY AND THE EASTERN EMPERORS The division of the Roman Empire led naturally to a grouping of the Christian Church about Rome and Constantinople, the two chief centers of government. The popes, it has been seen, had always enjoyed spiritual leadership in the West. In temporal matters they acknowledged the authority of the eastern emperors, until the failure of the latter to protect Rome and Italy from the barbarians showed clearly that the popes must rely on their own efforts to defend Christian civilization. We have already learned how well such men as Leo the Great and Gregory the Great performed this task. Then in the eighth century came the alliance with the Frankish king, Pepin the Short, which gave the Papacy a powerful and generous protector beyond the Alps. Finally, by crowning Charlemagne, the pope definitely broke with the emperor at Constantinople and transferred his allegiance to the newly created western emperor. RISE OF THE PATRIARCHATE OF CONSTANTINOPLE The patriarch of Constantinople, as bishop of the capital city, enjoyed an excellent position from which to assert his preeminence over the bishops of the other churches in the East. Justinian in 550 A.D. conferred on him the privilege of receiving appeals from the other patriarchs, and a few years later that dignitary assumed the high-sounding title of "Universal Archbishop." The authority of the patriarch of Constantinople was immensely strengthened when the Mohammedans, having conquered Syria and Egypt, practically extinguished the three patriarchates of Antioch, Jerusalem, and Alexandria. [31] The Church in the East now had a single patriarch, just as that in the West had the one bishop of Rome. Rivalry between them was inevitable. RIVALRY BETWEEN POPE AND PATRIARCH