The Diocese of Pensacola-Tallahassee celebrated the feast day of St. Irenaeus, a martyr and father of the Church, on Tuesday.

“Today is the feast of St. Irenaeus, bishop and martyr,” the diocese posted online. “Irenaeus was born in one of the maritime provinces of Asia Minor where the memory of the apostles was still cherished. His biggest influence was St. Polycarp, who had known the apostles or their immediate disciples. … St. Irenaeus, please pray for us!”

St. Irenaeus was born around the year 120 to a Greek family in Asia Minor. Britannica explains that he encountered St. Polycarp, the last living connection to Jesus' Apostles, before Polycarp was martyred in 155.

St. Irenaeus served as a missionary before becoming bishop of Lugdunum in 177. His early years were spent combatting heresies and on peacemaking missions between differing factions. For example, Britannica cites a time when the Roman church and the churches of Asia Minor disagreed over the date on which Easter should be celebrated, Irenaeus mediated between the two and emphasized that the difference was insignificant and should not disturb their unity.

In January, Pope Francis, describing Irenaeus as “a great spiritual and theological bridge between Eastern and Western Christians, said he would bestow the title of Doctor of the Church upon St. Irenaeus.

“Doctor of the Church” is a title that a pope can bestow upon a person who has made significant and lasting contributions to the church, according to Crossroads Initiative. Throughout the history, 36 people have been granted this title.

Crossroads Initiative lists three requirements for earning the title: “holiness that is truly outstanding, even among saints”; “depth of doctrinal insight”; and “an extensive body of writings which the church can recommend as an expression of the authentic and life-giving Catholic Tradition.”

Irenaeus is the patron saint of catechists and apologists, My Catholic Life says.