St. Irenaeus, one of the first systematic theologians of the Church, was born in Asia Minor. At some point he made his way to Lyons, a major Roman outpost in Gaul, where he was ordained a presbyter. In 177, while he was on a mission in Rome, a wave of savage persecution swept over the Church in Lyons. Upon his return Irenaeus found that his own bishop, Pothinus, was among the martyrs. He was chosen to take his place.  

In the rapid proliferation of Gnostic sects, Bishop Irenaeus came to believe the Church faced a threat even greater than persecution. One of the typical features of Gnosticism was a sharply dualistic understanding of matter and spirit. It was impossible for Gnostics to imagine any direct interaction between these two realms, either in the Christian doctrines of creation or in the incarnation.  

Irenaeus wrote his principal work to counter these ideas. He underscored the links between the Old and New Testaments, insisting on the identity between the God of creation and the God of salvation. There was nothing inherently corrupt in creation; it was only through the distortion of sin that human beings lost their “likeness to God.” This was restored in the obedience of Christ, who corrected the story of the first Adam. Only the God who created human beings could also save us; and only that which was truly assumed (humanity in the incarnation) could also be redeemed.  

Irenaeus died as a martyr sometime around the year 200.  

“The glory of God is the human being fully alive.”  

—St. Irenaeus