The date of his birth and his death are unknown. In the Roman province of Asia he founded a school and gathered disciples. None of Cerinthus' actual writings have survived. As is the usual case, we can interpret his teachings only through what his more orthodox enemies reported.
The earliest surviving account of Cerinthus is that of Irenĉus' refutation of Gnosticism, Adversus haereses (I: xxvi; III: iii and xi), which was written about 170 CE. According to Irenĉus, Cerinthus, a man educated in the wisdom of the Egyptians, claimed angelic inspiration. He taught that the visible world and heavens were not made by the supreme being, but by a lesser power (Demiurge) distinct from him. Not Jehovah but the angels have both made the world and given the law. These creator-angels were ignorant of the existence of the Supreme God. The Jewish law remained sacred and essential to salvation.
Cerinthus distinguished between the man Jesus and the Christ. He denied the supernatural birth of Jesus, making him the son of Joseph and Mary, and distinguishing him from Christ, who descended upon him at baptism and left him again at his crucifixion. Cerinthus is also said to have taught that Jesus will be raised from the dead at the Last Day, when all men will rise with Him.
He was thus similar to an Ebionite in his Christology, but Gnostic in his doctrine of the creation.
Cerinthus believed in a happy millennium which would be realized here on earth previous to the resurrection and the spiritual kingdom of God in heaven.
According to Irenaeus, Polycarp told the story that St. John the Divine, in particular, is said to have so feared Cerinthus that he once fled a bathhouse when he found out Cerinthus was inside, yelling "Let us flee, lest the building fall down; for Cerinthus, the enemy of the truth, is inside!"
Among the teachings of Cerinthus that were in opposition to the apostles and other early church fathers:
-- A lesser diety created the physical world
-- Jesus the man and "Christ" the godly spirit were not one in the same
-- Justification by works, in particular the ceremonial observances of Judaism.