Against Heresies

By his own account Irenaeus saw the aged Polycarp of Smyrna in his early youth (3.3.4). He later became bishop of Lyons in Gaul. He wrote in Greek. Most of the Greek is lost, and the whole work survives only in a Latin translation made in antiquity. He names Eleutherius as the bishop of Rome at the time of writing (3.3.3), which places the third book between about 175 and 189.

Book 1 describes the teaching of the Valentinians and of other groups that Irenaeus opposes. He writes as their adversary. Since the discovery of the Nag Hammadi codices in 1945 his reports can be compared with writings from such groups themselves. Books 3 to 5 argue from Scripture and from the teaching handed down in the churches. The passages cited most often are the account of how the four Gospels came to be written (3.1.1), the list of the bishops of Rome from the apostles to Eleutherius (3.3.3), and the argument that there can be neither more nor fewer than four Gospels (3.11.8). For the apostolic age Irenaeus is a witness to what was believed in the churches about a century later, not a contemporary.

One passage needs care with the online text. In 3.3.2 the printed translation reads that every church should agree with the church of Rome “on account of its pre-eminent authority, that is, the faithful everywhere, inasmuch as the apostolical tradition has been preserved continuously by those [faithful men] who exist everywhere”. The New Advent page (as read on 3 October 2026) stops at “preeminent authority” and omits the rest of the sentence, and it omits the translators’ note saying that they are unsure of the rendering. The CCEL page linked above gives both. The sentence survives only in the Latin version, and its meaning is disputed between the churches.