St. Irenaeus (about 130–202) was a Greek-speaking bishop of Lyon, in Gaul, who as a boy had listened to St. Polycarp, the disciple of the Apostle John, and who became the first great theologian of the Church, defending the faith handed down from the apostles against the Gnostic sects in his five books Against Heresies. He is the author of one of the most beloved sayings of the Fathers, “the glory of God is a living man,” and in 2022 Pope Francis declared him a Doctor of the Church with the title “Doctor of Unity.” His feast day is June 28. Below are his story, his own words, and prayers to St. Irenaeus for the unity of the Church.
A short prayer to St. Irenaeus, written for this page:
St. Irenaeus, you treasured the faith handed down from the apostles and worked for peace in the Church.
Pray for the unity of all Christians,
and help me to become fully alive in God, for His glory. Amen.
Who was St. Irenaeus?
Irenaeus was born around 130 in Asia Minor, probably at Smyrna, where as a young man he heard the aged bishop St. Polycarp tell what he had learned from St. John and others who had seen the Lord. Irenaeus later went to Gaul, to the Christian community of Lugdunum, today’s Lyon, and became a priest there. In 177 the church of Lyon sent him to Rome with a letter to Pope Eleutherius; while he was away, a fierce persecution broke out in which the aged bishop Pothinus and many Christians of Lyon were martyred. On his return Irenaeus was chosen bishop.
He wrote against the Gnostics, who claimed secret knowledge and taught that the material world was evil and that the God of the Old Testament was not the Father of Jesus. Irenaeus answered that there is one God, Creator of heaven and earth, that the Son of God truly became man, and that the true faith is the one taught openly by the apostles and handed down in the churches by the succession of bishops. When Pope Victor threatened to cut off the churches of Asia over the date of Easter, Irenaeus urged peace, living up to his name, which means “peaceful.” He died around 202; tradition honors him as a martyr.
“The glory of God is a living man”
From Against Heresies (IV.20.7):
For the glory of God is a living man; and the life of man consists in beholding God. For if the manifestation of God which is made by means of the creation, affords life to all living in the earth, much more does that revelation of the Father which comes through the Word, give life to those who see God.
The faith handed down from the apostles
Irenaeus pointed to the Church of Rome, founded on the apostles Peter and Paul, as the sure witness to the apostolic tradition (Against Heresies III.3.2):
Since, however, it would be very tedious, in such a volume as this, to reckon up the successions of all the Churches, we do put to confusion all those who, in whatever manner, whether by an evil self-pleasing, by vainglory, or by blindness and perverse opinion, assemble in unauthorized meetings; [we do this, I say,] by indicating that tradition derived from the apostles, of the very great, the very ancient, and universally known Church founded and organized at Rome by the two most glorious apostles, Peter and Paul; as also [by pointing out] the faith preached to men, which comes down to our time by means of the successions of the bishops. For it is a matter of necessity that every Church should agree with this Church, 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.
What is St. Irenaeus the patron saint of?
- Lyon, France
- Theologians and catechists
- Christian unity, as the “Doctor of Unity”
Prayers to St. Irenaeus
Written for this page.
For the unity of the Church
St. Irenaeus, Doctor of Unity, you built bridges between East and West.
Pray that all who believe in Christ may be one, as Jesus prayed. Amen.
For teachers of the faith
St. Irenaeus, pray for catechists and theologians,
that they may hand on the faith of the apostles faithfully, clearly and with love. Amen.
Feast day and Doctor of the Church
The memorial of St. Irenaeus, bishop, martyr and Doctor of the Church, is June 28. On January 21, 2022, Pope Francis declared him a Doctor of the Church with the title Doctor unitatis, “Doctor of Unity,” because his teaching serves as a bridge between Eastern and Western Christians.
Frequently asked questions
Who said “the glory of God is man fully alive”?
St. Irenaeus, in Against Heresies (IV.20.7): “For the glory of God is a living man; and the life of man consists in beholding God.”
Why is St. Irenaeus called the Doctor of Unity?
Because his teaching, rooted in both East and West, and his work for peace in the Church, help to build unity among Christians.
When is St. Irenaeus’s feast day?
June 28.
More saints
- Doctors of the Church
- St. Polycarp
- St. Ignatius of Antioch
- St. Justin Martyr
- Apostles’ Creed
- Solemnity of Sts. Peter and Paul
- Saint of the day
Texts and sources
- Irenaeus, Against Heresies IV.20.7 and III.3.2, trans. A. Roberts and W. H. Rambaut, Ante-Nicene Fathers, vol. 1 (1885), public domain (Wikisource).