Irenaeus

Irenaeus ( or ; ; ) was a Greek bishop noted for his role in guiding and expanding Christian communities in the southern regions of present-day France and, more widely, for the development of Christian theology by opposing Gnostic interpretations of Christian Scripture and defining proto-orthodoxy. Originating from Smyrna, he had seen and heard the preaching of Polycarp, who in turn was said to have heard John the Evangelist.

Chosen as bishop of Lugdunum, now Lyon, his best-known work is ''Against Heresies'', often cited as ''Adversus Haereses'', a refutation of gnosticism, in particular that of Valentinus. To counter the doctrines of the gnostic sects claiming secret wisdom, he offered three pillars of orthodoxy: the scriptures, the tradition said to be handed down from the apostles, and the teaching of the apostles' successors. He is the earliest surviving witness to regard all four of the now-canonical gospels as essential.

Irenaeus is venerated as a saint in the Catholic Church, Anglican Church, Lutheran Churches, the Eastern Orthodox Church, the Oriental Orthodox Churches, and the Assyrian Church of the East. He was declared a Doctor of the Church in the Catholic Church by Pope Francis in 2022. Provided by Wikipedia