One of the first and most significant indications of the new orientation of Muslim thought was the extensive production of Arabic translations of works dealing with philosophical and scientific subjects, with the result that eighty years after the f all of the Umayyads the Arabic speaking world possessed Arabic translations of the greater part of the works of Aristotle, of the leading neo-Platonic commentators, of some of the works of Plato, of the greater part of the works of Galen, and portions of other medical writers and their commentators, as well as of other Greek scientific works and of various Indian and Persian writings. This period of activity in translating falls into two stages, the first from the accession of the Abbasids to the accession of al-Mamum (A.H. 132-198), when a large amount of work was done by various independent translators, largely Christians, Jews, and recent converts from non-Islamic religions; the second under al-Mamun and his immediate successors, when the work of translation mainly centered in the academy newly founded at Baghdad, and a consistent effort was made to render the material necessary for philosophical and scientific research available for the Arabic speaking student. Al-Mansur, after founding Baghdad in A.H. 148 (= A.D. 765) summoned a Nestorian physician, George Boktishu, from the school at Junde-Shapur and established him a court physician, and from this time there was a series of Nestorian physicians connected with the court and forming a medical school at Baghdad. George fell ill in Baghdad and was allowed to retire to Junde-Shapur, his place being The most important work of the academy however was done by Yahya's pupils and successors, especially Abu Zayd Hunayn b. Ishaq al-Ibadi (d. 263 A.H. = A.D. 876), the Nestorian physician to whom we have already referred as translating into Syriac the chief medical authorities as well as parts of Aristotle's Organon. After studying at Baghdad under Yahya he visited Alexandria and returned, not only with the training given at what was then the first medical school, but with a good knowledge of Greek which he employed in making translations in Syriac and Arabic. The real impetus came ultimately from transmitted Hellenism, but this influence was derived immediately from the Nestorians in philosophy proper, and from the Nestorians and the Zoroastrian school at Junde-Shapur marsh lands near Basra, but they had always been careful to keep their religious beliefs secret from all outsiders, and although they were no doubt the sect mentioned in the Quran under the name of Sabiyun or Sabians, none could prove that the pagans of Harran were not also comprised under this term. The Khalif never did pass back by Harran, the pagans who had assumed the name of Sabian continued to use it, those who had become Christians or Zoroastrians reverted to their old faith and submitted to its new name; those who had become Muslims were obliged to remain so as the penalty of death lay upon any who became renegades from that religion. The most distinguished of the alumni of Harran was Thabit b. Qurra (d. 289 A.H.), a scholar familiar with Greek, Syriac, and Arabic, who produced many works on logic, mathematics, astrology, and medicine, as well as on the ritual and beliefs of the paganism to which he remained faithful. Following in his footsteps were his son Abu Said Sinan, his grandsons Ibrahim and Abu l-Hasan Thabit, and his great grandsons Ishaq and Abu l-Faraj. All these specialized in mathematics and astronomy. It seems that we ought to associate with Harran Jabir b. Hayyan a perfectly historical character but of somewhat uncertain date, but believed to have been a pupil of the Umayyad prince Khalid, who distinguishedTHE TRANSLATORS