Irenaeus of Lyons

Irenaeus was born in Asia Minor, about AD 130. As a boy he heard Polycarp of Smyrna. In a letter to Florinus, preserved by Eusebius, he recalls how Polycarp spoke of his dealings with John and with others who had seen the Lord. He later lived in Gaul, served as a presbyter in Lyons, and became its bishop after Pothinus died in the persecution of AD 177.

Two of his works survive. Against Heresies, written about AD 180 in five books, is preserved complete in a Latin translation, with parts in the original Greek. The Demonstration of the Apostolic Preaching, a short summary of the faith, is known only in Armenian and was rediscovered in 1904.

Against Heresies answers the Gnostic teachers, especially the Valentinians, who taught that the creator was a lesser being and the material world a flaw. Irenaeus answers that one God made all things good, that the Son truly became flesh, and that the faith is known from what the apostles taught, handed down openly in the churches and in their succession of bishops, not from secret knowledge. He argues that the church has four Gospels and no more (3.11.8), and he quotes from most of the books of the New Testament.

He also wrote to Victor, bishop of Rome, urging peace with the churches of Asia over the date of Easter. The date and manner of his death are not recorded by early witnesses. Later writers call him a martyr, about AD 202.