Cerdon, a Gnostic teacher of the first half of the 2nd cent., principally known as the predecessor of MARCION. Epiphanius and Philaster assert him to have been a native of Syria, and Irenaeus states that he came to Rome in the episcopate of Hyginus. This episcopate lasted four years, and Lipsius places its termination A.D. 139–141. Bearing in mind the investigations of M. Waddington concerning the year of Polycarp’s martyrdom, we prefer the earlier date, if not a still earlier one, and would put Cerdo’s arrival at Rome as early as A.D. 135.
According to the account of Irenaeus, Cerdo had not the intention of founding a sect apart from the church. He describes him as more than once coming to the church and making public confession, and so going on, now teaching his doctrine in secret, now again making public confession, now convicted in respect of his evil teaching, and removed, or, as some think, voluntarily withdrawing himself, from the communion of the brethren. Epiphanius seems inaccurate in giving a heading to a sect of Cerdonians. Preceding writers speak only of Cerdo, not of Cerdonians; and probably his followers were early merged in the school of Marcion, who is said to have joined himself to Cerdo soon after his arrival in Rome.
Apparently Cerdo left no writings, nor is there evidence that those who report his doctrine had any knowledge of it independent of the form it took in the teaching of his Marcionite successors. Consequently we can not now determine with certainty how much of the teaching of Marcion had been anticipated by Cerdo, or what points of disagreement there were between the teaching of the two. Hippolytus, in his Refutation, makes no attempt to discriminate between their doctrines. Tertullian, in his work against Marcion, mentions Cerdo four times, but only as Marcion’s predecessor. Irenaeus says that Cerdo taught that the God preached by the law and the prophets was not the Father of our Lord; for that the former was known, the latter unknown; the former was just, the latter good.
Pseudo-Tertullian’s account may be regarded as representing that in the earlier treatise of Hippolytus, which was also used by Philaster and Epiphanius. Thus we learn that Cerdo introduced two first principles and two gods, the one good, the other evil, the latter the creator of the world. It is an important difference that to the good god is opposed in the account of Irenaeus a just one; in that of Hippolytus, an evil one. In the later work of Hippolytus already cited, Cerdo is said to have taught three principles of the universe. Ps.-Tertullian goes on to say that Cerdo rejected the law and the prophets, and renounced the Creator, teaching that Christ was the son of the higher good deity, and that He came not in the substance of flesh but in appearance only, and had not really died or really been born of a virgin; and that Cerdo only acknowledged a resurrection of the soul, denying that of the body.
He adds, but without support from the other authorities, that Cerdo received only the Gospel of St. Luke, and that in a mutilated form; that he rejected some of Paul’s epistles and portions of others, and completely rejected the Acts and the Apocalypse. There is every appearance that here transferred to Cerdo what in his authority was stated of Marcion.