Irenaeus of Lyons
BIOGRAPHY
Irenaeus (Greek: Εἰρηναῖος, Eirēnaîos; c. 130 – c. 202 AD) was a Greek bishop renowned for his pivotal role in guiding and expanding Christian communities in the southern regions of present-day France, as well as for his significant contributions to the development of Christian theology. He is most noted for his vigorous opposition to Gnostic interpretations of Christian Scripture and for defining proto-orthodoxy.
Originally from Smyrna, Irenaeus had the privilege of hearing the preaching of Polycarp, who, in turn, was said to have been taught by John the Evangelist. Irenaeus became the bishop of Lugdunum (modern-day Lyon), where he authored his most famous work, Against Heresies (Latin: Adversus Haereses), a critical refutation of Gnosticism, particularly the teachings of Valentinus. To counter the claims of Gnostic sects, which purported to possess secret wisdom, Irenaeus established three pillars of orthodoxy: the Scriptures, the tradition passed down from the apostles, and the teaching of the apostles' successors. He is also the earliest surviving witness to recognize all four of the now-canonical Gospels as essential to the Christian faith.
Irenaeus is venerated as a saint by the Catholic Church, Anglican Church, Lutheran Churches, Eastern Orthodox Church, Oriental Orthodox Churches, and the Assyrian Church of the East. In 2022, Pope Francis declared him a Doctor of the Church.