Irenaeus of Lyon

Irenaeus grew up in Asia Minor, where he heard Polycarp of Smyrna, and became bishop of Lugdunum (Lyon) in Gaul around 177. Britannica describes him as a leading theologian of the second century who helped shape the biblical canon, creeds, and the authority of bishops. He died around 200.

His major work, Against Heresies, written around 180 CE, attacks the Gnostic groups of his day and summarizes their teachings in order to refute them. For centuries it was one of the main sources on Gnostic belief, until the Nag Hammadi codices, found in 1945, let scholars read Gnostic texts in their own words.

In Book 1, chapter 30, Irenaeus describes a group whose myth includes Ialdabaoth, the arrogant offspring of Sophia who creates the world and boasts that he alone is God. The same figure, spelled Yaldabaoth, appears in the Apocryphon of John and the Hypostasis of the Archons from Nag Hammadi, which shows Irenaeus was reporting real teachings.