Irenaeus taught that there were four authoritative Gospels: Matthew, Mark, Luke, and John Symbols of the four Gospels: Matthew-man, Mark-winged lion, Luke-ox, John-eagle

Irenaeus was born in Smyrna and served as bishop in Europe. His most important surviving work, Against All Heresies, is an attack on both gnosticism and Montanism. His own theology, expressed in the Demonstration of the Apostolic Preaching, is a presentation of early western catholic belief. Irenaeus strongly emphasizes the work of God in history and the humanity of Christ in the incarnation. He is noted for the concept of recapitulation according to which Christ, as a second Adam, renews and restores the work of God in creation.