Saint Irenaeus

Irenaeus, also known as Εἰρηναῖος (Eirēnaîos), was a Greek bishop active during the second century AD, noted for his role in guiding and expanding Christian communities in southern France and beyond. Born in Smyrna, he had witnessed and heard the preaching of Polycarp, who claimed to have heard from John the Evangelist. Chosen as Bishop of Lugdunum (now Lyon), Irenaeus authored 'Against Heresies' around 180 AD, a seminal work refuting Gnostic interpretations of Christian Scripture. In his writings, he emphasized three pillars of orthodoxy: the scriptures, apostolic tradition, and teaching from apostolic successors. His work was instrumental in establishing the four canonical gospels as essential to Christian doctrine.