This is the first instalment of an ongoing series: Introduction to the Church Fathers. In this series we will explore the life, times and teachings of some of the most important figures in the early church and what they can teach us today. This article explores the life and writings of St Irenaeus of Lyon.

Historical Context

The exact date of Irenaeus’ birth is disputed. What we do know is that he was born sometime in the first half of the second century, between 120 and 140 AD. As such, he a valuable witness to the life and faith of the very early church. What we also know is that in his youth he saw and heard speak Polycarp, Bishop of Smyrna – a moment of great profundity for Irenaeus since Polycarp was the last remaining connection to the apostles, being a disciple of the apostle John.

Irenaeus first came to public prominence during the rule of Emperor Marcus Aurelius (161-180 AD), the famous Emperor-Philosopher whose little book Meditations is a staple of almost every modern bookshop (the one to whom Justin Martyr also wrote an Apologia around this time). An important historical source for Irenaeus comes from Eusebius of Caesarea’s Ecclesiastical History. Even though he was born in the east, somewhere in Asia Minor, Irenaeus ended up in the west, in Lyon, France, where he became a priest. He obviously displayed himself to be a man of great capability because in the year 177 AD he was sent to Rome on behalf of the churches of Lyon and Viennes in order to seek a peaceful resolution to the Montanist controversy.

Montanism was, in essence, a ‘charismatic’ movement that gained great popularity between the second and fourth centuries. Although none of the original Montanist writings have survived, it seems clear that Montanus and his followers, beginning in the mid 150s AD, believed that the Holy Spirit was continuing to reveal itself through them, preparing the church for the imminent coming of Jesus Christ by way of a rigorous moralism (even condemning some things the Church did not see to be wrong). Part of the theological problem with Montanism was the belief that Divine Revelation was continuing through their prophetic utterances instead of having been handed down ‘once and for all’ to the faithful (Jude 1:3).

It was in his interactions with the Bishop of Rome, Eleutherius, that he was seen also to live up to his name (‘irenic’ meaning the ‘aiming at peace’). While he was away, however, a bloody persecution took place in Lyon and Viennes. Over forty Christians were tortured to death at the Lyon Roman amphitheatre, the remains of which exist to this day. The bishop of Lyon was killed also, and upon Irenaeus’ return from Rome he was appointed bishop in the man’s stead.

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According to Eusebius, Irenaeus was a prolific writer and often wrote against the heresies of his day. Much has been lost, but what has survived is invaluable in trying to understand the early church and the influence of Gnosticism. Irenaeus’ surviving text, Against Heresies, is a five-book work that argues against some of the most influential Gnostics of his day.

Gnosticism, famously, is the general belief that the ‘spiritual’ element in the world is higher and in competition with the more ‘material’ or ‘baser’ elements. The word gnosis means ‘knowledge’, and usually it was through the achievement of this ‘knowledge’, or ‘mystery’, that man was able to be saved, to escape the base, fleshly outfit he wears for only a limited time. Usually Gnostic communities were somewhat elitist in that it was only to the ‘perfect’ or the ‘initiated’ that this knowledge was revealed. Gnostics tended to think that in Jesus Christ, God did not really take on human flesh because God is an eternal spiritual being and would not do such a thing. Jesus only appeared to be human.

Much of Irenaeus’ writings are against this prevalent belief. In terms of our connection with the historical church, his Against Heresies are revealing on a number of counts.

Witness to Apostolic Succession

Irenaeus’ argument runs like this: if, as the Gnostics say, the faith consists in some secret ‘mystery’ that only the perfect can understand, then surely the apostles would have handed on this mystery to the bishops, who are the successors to the apostles and were appointed by them. The bishops are there to serve the church and hand on this faith – surely they are privy to this knowledge. In point of fact, he argues, the faith is not a secret mystery only the perfect can come to know. The faith is that which is handed down to us by the apostles through their successors. Interestingly, he also points out that the Church was ‘founded and organized at Rome’ by Peter and Paul, and it is Rome that has ‘preeminent authority’ (Book III, Chapter III).

Witness to belief in the Eucharist

One of the problems Gnostics tended to have was with the Eucharistic theology of the Church. This is seen not only in Irenaeus but Ignatius of Antioch, too. If God would not deign to actually take on human flesh, then he certainly would not commune with his people through the Eucharistic species of bread and wine, base and material things. It is here that we can see on display in Irenaeus something of a raw and primal Eucharistic theology: when the bread and the wine ‘receive the Word of God’ they become ‘the body and blood of Christ’; through our participation in the body and blood of Christ, eternal life is given to our corruptible mortal bodies, and they will rise again in the resurrection of the just (Book V, Chapter II).

Witness to belief in the resurrection of the body

A running theme throughout seems to be that Gnostics denied the resurrection of the body. Because mortal flesh is corruptible and subject to decay, it can have no place in an eternal spiritual kingdom. Much of the five books that form Against Heresies deal with this problem. Using Scripture and the faith of the apostles, Irenaeus argues that whilst flesh is indeed corruptible, through the grace of Christ it can become incorruptible. The New Testament is at great pains to emphasise the flesh and blood of Jesus, because precisely in taking on actual flesh Jesus ‘summed up human nature in His own person’, restoring in himself what was once lost (Book V, Chapter XIV). The Christian hope was never for an ethereal, disembodied afterlife – it was for the restoration of all creation.

In refuting the Gnostics, Irenaeus was able to demonstrate the lack of uniformity in Gnostic teachings and their falsification of Christian doctrine. His works, along with that of other early church figures, helped provide the framework upon which Christian orthodoxy would come to be grounded, namely the rule of faith (creed), the canon of Scriptures and apostolic succession.