It will be noted that Zindiqism is mentioned as propagated by Ibn al-Muqaffaʿ, and is traced to Ibn Daysan amongst others, and this is precisely the same as the one whom Maqrizi names as the reputed progenitor of Maymun. Evidently the charge which lay at the bottom of this latter statement originally meant that Maymun was a Zindiq, and so could be described as a follower of Ibn Daysan, not that he actually was Ibn Daysan’s son, which would be an absurd anachronism. For the name Ibn Daysan refers to a perfectly genuine historical person: the Ibn Daysan of the Arabic writers was the Bar Daisan of Syriac literature, a convert from paganism to Christianity who died about A.D. 222, and whose followers formed an important sect at Edessa for several centuries, though in Muslim times he appears as a semi-legendary character. We possess a work probably written by one of his pupils called “A treatise on Fate” in the Christian writers, from which two lengthy extracts appear in Eusebius: _Praep. Evangel._ vi. 9, one of which is cited also in _Clementine Recognitions_ ix., but is headed “Book of the Laws of Countries” in the Syriac text discovered by Cureton, and published by him in 1855. Various references are made to Bar Daisan in Euschius, Epiphanius, and other Church Fathers, as well as in the dialogues ascribed to Adamantius, but our best information as to his teaching is to be obtained from Moses bar Kepha (_Patrol. Syr._, I., ii. 513-5), whose summary is fully endorsed by the controversial essays of St. Ephraim, who settled at Edessa in 363 when the Bar-daisanites were a real force there. Bar Daisan’s doctrine, which is a kind of Christianized Zoroastrianism, is described by Prof. Burkitt in his introduction to Mitchell’s edition of St. Ephraim’s _Prose Refutations_. Marcion represents an earlier and more definitely Christian system which at one time had a very wide extension, and probably was the medium through which Bar Daisan learned Christianity. It was a kind of dualistic system with two powers, the Good God and the Evil One. The Evil One was the creator whom the Jews worshipped as God, and the Good God sent his Son on earth to save men from this delusion: as in Zoroastrianism the two rival powers maintain an unceasing strife until the day of judgment when the good God will be finally victorious. From St. Ephraim we learn that the Marcionites long retained their hold in Northern Mesopotamia side by side with the Bar-daisanites.