3. After the victory of Moawiya, who made Damascus the capital of the Muslim empire, the importance of Medina lay mainly in the spiritual province. It had to content itself with fostering, partly under Jewish and Christian influences, a knowledge of the Law and Tradition. In Damascus, on the other hand, the Omayyads (661–750) conducted the secular government. Under their rule the empire spread from the Atlantic to districts beyond the frontiers of India and Turkestan, and from the Indian Ocean to the Caucasus and the very walls of Constantinople. With this development, however, it had reached its farthest extension. Arabs now assumed everywhere the leading position. They formed a military aristocracy; and the most striking proof of their influence is the fact, that conquered nations with an old and superior civilization accepted the language of their conquerors. Arabic became the language of Church and State, of Poetry and Science. But while the higher offices in the State and the Army were administered by Arabs in preference, the care of the Arts and Sciences fell, first of all, to Non-Arabs and men of mixed blood. In Syria school-instruction was received from Christians. The chief seats of intellectual culture, however, were Basra and Kufa, in which Arabs and Persians, Muslims, Christians, Jews and Magians rubbed shoulders together. There, where trade and industry were thriving, the beginnings of secular science in Islam must be sought for,—beginnings themselves due to Hellenistic-Christian and Persian influences. 4. The Omayyads were succeeded by the Abbasids (750–1258). To obtain the sovereignty, the latter had granted concessions to the Persians, and had utilized religio-political movements. During the first century of their rule (i.e. up to about 860), though only during that period, the greatness of the empire continued to increase, or at least it held its own. In the year 762, Mansur, the second ruler of this house, founded Bagdad as the new capital,—a city which soon outshone Damascus in worldly splendour, and Basra and Kufa in intellectual illumination. Constantinople alone could be compared to it. Poets and scholars, particularly from the North-Eastern provinces, met together in Bagdad at the court of Mansur (754–775), of Harun (786–809), of Mamun (813–833), and others. Several of the Abbasids had a liking for secular culture, whether for its own sake or to adorn their court, and although they may often have failed to recognize the value of artists and learned men, these at any rate could appreciate the material benefits conferred upon them by their patrons. From the time of Harun at least, there existed in Bagdad a library and a learned institute. Even under Mansur, but especially under Mamun and his successors, translation of the scientific literature of the Greeks into the Arabic tongue went forward, largely through the agency of Syrians; and Abstracts and Commentaries bearing upon these works were also composed.