Born in what is now Turkey, Irenaeus played a significant role in the establishment and then expansion of the early Christian communities in what is now southern France. But it was his fight against heresy that he is most remembered for. 

Irenaeus once heard St. Polycarp preaching and St. Polycarp is understood to have directly heard the words of St. John the Baptist and the Apostles. 

Becoming a priest, he served under the first Bishop of Lyon, St. Pothinus. At one point, Pothinus sent Irenaeus to Rome and, while he was gone, Pothinus was martyred during the persecution of Marcus Aurelius. 

When he returned, Irenaeus became the second bishop of Lyon. His battle was less with the Roman Emperor than the numerous heresies of the time, especially Gnosticism. 

Irenaeus wrote several books which were fundamental to the formation of Christianity. The first of which was entitled: “Against Heresies.” 

He was also the first to show that all four Gospels, Mathew, Mark, Luke, and John, were part of the Canonical Structure. 

Prior to his writings, some groups had preferences for Mark or Luke while ignoring the others. 

Irenaeus also showed that God formed the world and has been overseeing it since its creation. And, he defined Salvation by the extensive use of the Epistles of Paul. 

He saw Christ as the new Adam and Mary as the new Eve, whose obedience to the direction of God overcomes Eve’s disobedience. 

He is believed to have been martyred around 202. 

St. Irenaeus, please pray for us.