Early Sources
Irenaeus’s book Against Heresies provides extensive treatment of what Gnostics believed. Three Coptic Gnostic codices were published. Two were discovered in Nag Hammadi, Egypt in 1945. Codex Askewianus contains Pistis Sophia and Codex Brucianus contains The Book of Jeu. Best known among the Nag Hammadi documents is the Gospel of Thomas. A third work from this period, Codex Berolinensis, was found elsewhere and published in 1955. It contains a Gospel of Mary [Magdalene], a Sophia of Jesus, Acts of Peter, and an Apocryphon of John. The first translation of a tractate, The Gospel of Truth, appeared in 1956, and a translation of fifty-one treatises, including Gospel of Thomas, appeared in 1977.
Leaders
The early fathers of the church held that Gnosticism had first-century roots and that Simon the Sorcerer of Samaria (Acts 8) was the first Gnostic. According to church fathers, Simon practiced magic, claimed to be divine, and taught that his companion, a former prostitute, was reincarnated Helen of Troy. Hippolytus (d. 236) attributed the Apophasis Megale to Simon. Simon’s disciple, a former Samaritan named Menander, who taught in Syrian Antioch near the end of the first century, taught that those who believed in him would not die. That claim was nullified when he died.
At the beginning of the second century, Saturninus (Satornilos) asserted that the incorporeal Christ was the redeemer, denying that Christ was really incarnated in human flesh. This belief is shared with docetism. In this period Cerinthus of Asia Minor was teaching adoptionism, the heresy that Jesus was merely a man upon whom Christ descended at his baptism. Since Christ could not die, he departed from Jesus before his crucifixion. Basilides of Egypt was called both a dualist by Irenaeus and a monist by Hippolytus.
One of the more controversial, though atypical, Gnostics was Marcion of Pontus. He believed that the God of the Old Testament was different from the God of the New Testament and that the canon of Scripture included only a truncated version of Luke and ten of Paul’s Epistles (all but the pastoral Epistles). His views were severely attacked by Tertullian (ca. 160s–ca. 215). Marcion became a stimulus for the early church to officially define the limits of the canon.
Valentinus of Alexandria was another prominent Gnostic. He came to Rome in 140 and taught that there were a series of divine emanations. He divided humanity into three classes: (1) Hylics or unbelievers, who were immersed in material and fleshly nature; (2) psychics or common Christians, who lived by faith and pneumatics; and (3) spiritual Gnostics. His followers included Ptolemaeus, Heracleon, Theodotus, and Marcus. Heracleon’s interpretation of John is the first known New Testament commentary.
Gnostic-like beliefs persisted into the fourth century. Among the late manifestations was Manichaeism, a dualistic cult that trapped Augustine in his pre-Christian life. Against it he wrote many treatises, which are collected in The Anti-Manichaean Writings in the Ante-Nicene Fathers.