Church history: Irenaeus and the Second Century Church

Irenaeus has been called the most important Christian theologian between the apostles and the third century. He was a Greek born in Roman Proconsular Asia, today southwestern Turkey, probably between A.D. 130-140. Raised in a worshipful Christian home, as a youth he heard and knew the bishop of Smyrna, Polycarp (c. 70-155). Irenaeus explained how Polycarp spoke of his conversations “with John [the apostle] and with the others who had seen the Lord.”1

When a young man, Irenaeus migrated to Lugdunum, Gaul (modern Lyons, in France). He became a missionary to the Celts and eventually an elder in the Lyons congregation. Later, Irenaeus was ordained the second bishop of Lyons, replacing Pothinus, age 90, who had been martyred.

Irenaeus died perhaps around the end of the second century. His last known appearance occurs when he writes a firm but respectful letter of protest to Victor, the bishop of Rome between 189-199. Victor wanted to excommunicate the Christians of Asia because they kept the church’s traditional Paschal festival on Nisan 14.

Against the heretics

His widely-circulated theological work in five books was titled On the Detection and Refutation of the Knowledge Falsely So Called. Written about 175-185, it exposed the heresies of various Gnostic sects, especially the most sophisticated group, the Valentinians.

Irenaeus lived too late to personally hear the apostles and their disciples speak or teach. He relied on the succession of bishops in each major city to provide a theological and faith link between himself and the apostles. He gave special attention to the succession of bishops in the church at Rome as an example of the deposit of apostolic tradition that could be found in other churches. Irenaeus cites this succession as “a complete proof that the life-giving faith is one and the same, preserved and transmitted in truth in the church from the apostles up till now.”2

Irenaeus also relied heavily on the teaching of the New Testament to refute the claims of the heretics. He explained that in the church’s writings can be seen “the unfeigned preservation, coming down to us, of the scriptures, with a complete collection allowing for neither addition nor subtraction.”

Irenaeus “is the first writer whose New Testament virtually corresponds to the canon that became accepted as traditional.”3 He quotes from most of its writings, though he doesn’t cite Philemon, James, 2 Peter or 3 John. We can’t say whether he knew of these letters, or if he did,
what his view might have been of their authority for the church.

Irenaeus was the first Christian writer to list all four Gospels as authoritative for the church. He said that through them “the tradition of the apostles, manifest in the whole world, is present in every church to be perceived by all who wish to see the truth.”

Trinitarian theology

Irenaeus testified to the church’s Trinitarian understanding of God’s nature long before the councils of Nicaea (325) and Constantinople (381) produced their traditional confessional creed. “In his various statements of faith there appear all the essentials of the Creed of Nicaea except its technical terms.”4

Irenaeus explained that the church “received from the apostles and their disciples the faith in one God the Father Almighty…and in one Christ Jesus, the Son of God, incarnate for our salvation, and in the Holy Spirit.” He also insisted that God’s word witnesses to the Son of God in the Incarnation being fully God as well as true human. “All the prophets and apostles and the Spirit itself” testify to this, he said.

Irenaeus believed that Jesus’ redemptive work in his Incarnation, perfect life, death and resurrection was a “Victory in Christ” over all of God’s enemies. He wrote: “[Christ] fought and was victorious…for he bound the strong man, liberated the weak, and by destroying sin endowed his creation with salvation.”

Irenaeus’ legacy is his struggle to preserve and pass on the revelation of God that had been given to the apostles. It’s no wonder both the Roman Catholic and Eastern Orthodox churches consider him among the special “saints” of the church. Catholics celebrate a day in his honor each June 28.


1. Eusebius, The History of the Church from Christ to Constantine, bk. 5.20.6.

2. Quotes of Irenaeus are from On the Detection and Refutation of the Knowledge Falsely So Called, translated by Robert M. Grant, in Irenaeus of Lyons.

3. Henry Chadwick, The Early Church, 81.

4. Cyril C. Richardson, editor, Early Christian Fathers, 350.

Author: Paul Kroll

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