Irenaeus of Lyons

Irenaeus (c. 130–202 AD) was bishop of Lyons in Gaul and one of the most important theologians of the early Church. Born in Asia Minor — his exact city of birth is not recorded — he heard the preaching of Polycarp of Smyrna in his youth, providing a direct link to the apostolic generation. His monumental work Against Heresies systematically refuted Gnostic teaching and articulated the doctrine of apostolic succession and the rule of faith. He also served as an emissary to Rome on behalf of the churches of Gaul, and tradition holds he died a martyr at Lyons around 202 AD.