IRENAEUS of Lyons (130-202AD, 23rd August)
Irenaeus is the most pre-eminent scholar of the 2nd Century Christian Church. Born in Smyrna as a disciple of the famous Polycarp (and therefore a spiritual grandson of the Apostle John), he travelled west to become Bishop of Lyons in what is now France.
His definitive text, Against Heresies, does exactly what it says on the tin – it is a voluminous work that rebukes, rebuts and corrects the various heresies of his time, including Gnosticism and Marcionism. He does this by several means, including quoting from the Old Testament, confirming the validity of only four Gospels, quoting Paul’s epistles, as well as works like the Didache, 1 Clement and the Shepherd of Hermas. But most crucially, Irenaeus cites Apostolic succession – that his teachings are the same as those handed down to him by the Bishops from the Apostles, and especially from Rome – the See of Peter and Paul. He places great stock in his claim that what he advocates is unchanged from the Apostles, whereas the heretics have altered teachings.
It is in Irenaeus that we also see a developed Mariology, where she is cited as the New Eve, who restores with her obedience what the old Eve corrupted by her disobedience. His writings show that, even a mere century after the repose of the Apostles, Church dogma was clearly defined and guarded, and that there was an established Orthodox Church. It is also as revealing to note what is not discussed as well as what is disputed between Christian sects.
Irenaeus is thought to have been martyred, though details of his death are unknown, in 202AD.