Titian (Tatianus), an ecclesiastical writer of the 2d century, the time and place of whoso birth and death are uncertain, though he calls himself an Assyrian. He had received the education of a Greek, and been a teacher in the pagan schools before he went to Rome, where he practised as a teacher of eloquence, became the associate of Justin Martyr, and was converted to Christianity. After the death of Justin (about 165), he seems to have returned to the East, and adopted views resembling those of the Gnostic Marcion on the dual principle of good and evil, and on the essential depravity of matter. He became the founder of a sect known as Tatianists, forbade marriage and the use of animal food and wine, substituted water for wine in the service of the eucharist, and required the giving up of worldly goods as the evidence of Christian sanctity. His "Discourse to the Greeks" (Πρός "Ελληνας ), written while he still held orthodox opinions, has passed through many editions, the earliest being that of Zurich in 1546, and the best that of Oxford (8vo, 1700). The account of Tatian and his opinions is best given by Le Nourry in Worth's edition of his works; by the Benedictine Ceillier, in vol. ii. of his Auteurs sacres et ecclesiastiques; and by Daniel in Tatian der Apologet (Halle, 1887).