This remnant of the Roman Empire, with its capital on the confines of Europe and Asia, was an anomalous thing. It is a wonder that it continued to exist at all. In fact, there is no better evidence of the immense solidity of Roman political organization than the prolonged life of the Eastern Empire. The countries under its sway, Thrace, Illyria, Greece, Asia Minor, Syria, Palestine, Egypt, had no bond to hold them together, except common submission to one central authority. By the end of the sixth century, the Roman Empire was really Greek. The Greek language was spoken almost exclusively in Constantinople, Latin having dropped even from official use. Yet the Empire was still regarded as the Roman Empire, and was looked up to by the young Barbarian kingdoms of Europe with the respect which they deemed due to the Empire of Augustus and Trajan. For instance, a king of the Franks addresses the Emperor thus: "Glorious, pious, perpetual, renowned, triumphant Lord, ever Augustus, my father Maurice, Imperator," and is content to be called in return, "Childipert, glorious man, king of the Franks." Yet it must be remembered that Constantinople at this time was the chief city of Europe. Greek thought and Greek art lingered there. Justinian had just built St. Sophia. In fact, Constantinople continued for centuries to be the most civilized city in the world. The Imperial government was an autocracy; all the reins, civil, military, ecclesiastical, were gathered into the hands of the Emperor. Its foreign policy was to repel its enemies, Persians to the east, Avars to the north, Arabs to the south; its domestic policy was to hold its provinces together and to extort money. The Emperors, many of whom were able men, usually spent such time as could be spared from questions of national defence and of finance in the study of theology, for at Constantinople the problems of government were in great measure religious. Next to the actual physical needs of life, the main interest of the people was religion. A statesman who sought to preserve the Empire whole, of necessity endeavoured to hold together its incohesive parts by means of religious unity. This political need of religious unity is the explanation, in the main, of the frequent theological edicts and enactments.