Selected Works of Irenaeus of Lyons

Irenaeus is the most important theologian of his century. His book Against Heresies, essentially against the Gnostics and the Marcionites, is an essential work for students of history and the development of the church in the first centuries of Christianity. But Irenaeus, as an apologist, does not limit himself to unmasking errors; at the same time, he offers the answer, providing an argued and defined exposition of the Christian faith in which the church is still easily recognized today.

Irenaeus builds his arguments to establish true Christian doctrine on the rock of Christ's true, open testimony, communicated by his direct and immediate apostles through their writings. In contrast, the heretics of his time, to validate their own claims, resorted to the shadowy argument of a supposed secret testimony of Jesus, entrusted to alleged apostles from his inner circle and believed to have disappeared.

Today, the controversy that began in Irenaeus's time has returned to prominence due to the discovery in Egypt of a Coptic version (3rd or 4th century) of one of those lost Gnostic texts, of which only citations and condemnations by Irenaeus himself were known. This is the so-called Gospel of Judas, an apocryphal text from the 2nd century, which Irenaeus attributes to the Gnostic sect of the Cainites, and whose restoration, translation, and widespread dissemination opened up a significant controversy and caused considerable confusion for many people not expert in the subject. Irenaeus's work helps to clarify many misunderstandings, while offering us a broad overview of the many deviations that early Christianity had to face.