Marcion (mär´shən, mär´sēən), c.85–c.160, early Christian bishop, founder of the Marcionites, one of the first great Christian heresies to rival Catholic Christianity. He was born in Sinope. He taught in Asia Minor, then went (c.135) to Rome, where he perfected his theory. In 144 he was excommunicated from the church. He then formed a church of his own, which became widespread and powerful. Marcion taught that there were two gods, proclaiming that the stern, lawgiving, creator God of the Old Testament, and the good, merciful God of the New Testament were different. He considered the creator god the inferior of the two. Marcion also rejected the real incarnation of Christ, claiming that he was a manifestation of the Father. Though generally seen as one of the most important leaders of the somewhat loosely defined movement known as Gnosticism, he did not share some of the main premises of other Gnostic sects. He believed in salvation by faith rather than by gnosis; he rejected the Gnostic emanation theory; and he sought truth in his own truncated version of the New Testament, which included only 10 of the so-called Pauline Epistles and an edited version of St. Luke. He completely rejected the Old Testament. He explained in his Antitheses that since Jewish law was often opposed to St. Paul, all passages in the Bible that suggested the Jewish foundation of Christianity should be suppressed, even including such statements by St. Paul (see antinomianism). Marcionism emphasized asceticism and influenced the developments of Manichaeism, by which it was later absorbed. Its effect on orthodox Christianity was to cause a canonical New Testament to be assembled and promulgated and the fulfillment of the Old Law in the New Law to be clearly enounced.