Theologian · Patristic
St. Irenaeus of Lyons
c. 130–202 · Early Catholic tradition
Doctor of the Church (Doctor Unitatis, declared 2022); bishop and martyr, disciple of St. Polycarp who knew St. John.
Born in Smyrna, bishop of Lyons in Gaul. Against the Gnostics he defended the one Creator God, the goodness of matter and the flesh, the unity of the Old and New Testaments, and the resurrection of the body. He taught that Christ “recapitulated” all things, that Mary is the new Eve, and that the true faith is found in the public tradition of the churches founded by the apostles, above all Rome, “with which every church must agree.”
Why he matters: He is the first great theologian of Tradition, apostolic succession and the goodness of creation; his “the glory of God is a living man” and his vision of man growing into the likeness of God are foundational for both Latin and Greek theology.
Where to be careful
He held a literal millenarian reading of the thousand years of Apocalypse 20, which the Church later set aside.
Documented positions
Where this thinker stands on each dispute the test covers.