The East in a great measure owed its acquaintance with the rich treasures of Greek literature to the heresy of Nestorius. Nestorius was a Syrian by birth, and became bishop of Constantinople. Having denied that the Virgin Mary ought to be called “Mother of God,” he was summoned to appear before the Council of Ephesus (A.D. 431), and was deposed. Nestorian communities were formed, and the heretical opinions rapidly spread, patronized as they were for political purposes by the Persian kings. The Mahometan conquests in the seventh century, by overthrowing the supremacy of orthodoxy, afforded great encouragement to the Nestorians, as by denying that Mary was the mother of God, as the Catholics maintained, the Nestorians in calling her the mother of Christ more nearly approached the Mahometan conception of a pure monotheism. Barsumas, or Barsaumas, bishop of Nisibis (435-485 A.D.), was one of the most eminent leaders of the new heresy. He succeeded in gaining many adherents in Persia. Maanes, bishop of Ardaschiv, was his principal coadjutor; he was the means of propagating the Nestorian doctrines in Egypt, Syria, Arabia, India, Tartary, and even China. THE CALIPHS. In the time of Mohammed himself (569-609), the Arabians had physicians who had been educated in the Greek schools of medicine living amongst them. Pococke mentions a Greek physician named Theodunus, who was in the service of Hajáj Ibn Yúsuf in the seventh century. He wrote a sort of medical compendium for the use of his son. Hajáj seems also to have employed another Greek doctor named Theodocus, who had numerous pupils.[679] The House of Ommiyah encouraged the cultivation of the sciences. The Caliph Moawiyah, who resided at Damascus, founded schools, libraries, and observatories there, and invited the learned of all nations, especially Greeks, to settle there, and teach his people their arts and sciences.[680] In the seventh century, Alexandria under the rule of Islam was in possession of many medical schools in which the principles of Galen were taught.[681] Alkinani, an Arabian Christian, who afterwards was converted to Islamism, was chiefly instrumental in introducing medical teaching into Antioch and Harran from Alexandria.[682] The Caliph Almansor had studied astronomy. Almamon, the seventh of the Abbassides, collected from Armenia, Syria, and Egypt all the volumes of Grecian science he could obtain; they were translated into Arabic, and his subjects were earnestly exhorted to study them. “He was not ignorant,” says Abulpharagius, “that they are the elect of God, His best and most useful servants, whose lives are devoted to the improvement of their rational faculties.” Succeeding princes of the line of Abbas, and their rivals the Fatimites of Africa and the Ommiades of Spain, says Gibbon, were the patrons of the learned, “and their emulation diffused the taste and the rewards of science from Samarcand and Bochara to Fez and Cordova.”[683]