SECOND CENTURY. Anti-Gnostic apologist. All that is known of him is recorded in Eusebius, Ecclesiastical History (5.13). Born in Asia Minor, a disciple of Tatian in Rome, he wrote against the Marcionites. In particular, he had a confrontation with Apelles, an aged disciple of Marcion* in Rome. He also wrote a commentary on the Hexaemeron.