Feast Day : June 28 (West); August 23 (East)
Name meaning: Lover of peace
The writings of Irenaeus rank him among the greatest of the fathers of the church; he is considered the first great Christian theologian. His work—much of it still extant—helped to lay the Gnostic heresy to rest and laid the foundations of Christian theology. Although he wrote in Greek, he was quickly translated into Latin, and was highly influential in his day. Irenaeus was born in Asia Minor, probably around the year 130 (between 125 and 142), although some scholars believe earlier, between 115 and 125. This area had been heavily worked by the Apostles, and their memory would have been strong. While still very young, he heard St. Polycarp preach at Smyrna. Irenaeus joined the Christian priesthood and was sent as a missionary to the Church of Lyons in Gaul during the time of Emperor Marcus Aurelius’s bloody persecution of Christians. In 177 or 178 he was sent to Rome to deliver a letter asking for mercy on Montanism, a heretical sect, to Pope St. Eleutherius (r. 175–189), and thus escaped the persecutions in Lyons that resulted in the martyrdom of Bishop St. Pothinus. When he returned to Lyons, he was elected to the vacant bishopric, and remained in that capacity for the rest of his life. He spent his time preaching and traveling in missionary work, especially targeting pockets of Gnosticism in Gaul. The persecutions having subsided, Irenaeus found the greatest challenge to the Christian Church in Gnosticism, and set about clarifying the errors of the various sects in relation to the true teachings of the Apostles. He also took a stand on the Quartodeciman controversy concerning the celebration of Easter, interceding with Pope St. Victor (r. 189–199) in 190 or 191 to lift the sentence of excommunication upon the Christian communities of Asia Minor. Irenaeus is believed to have died in 202, although this is not certain. Probably he died a natural death. His remains were interred in a crypt under the altar of what was then known as the Church of St. John, but later called after him. The tomb became a shrine and was destroyed by Calvinists in 1562; all trace of his relics has been lost. Irenaeus wrote numerous treatises and letters and has been quoted by numerous church theologians since. He was vigorous in his defense of orthodoxy and in his opposition to heresy. Composed in Greek, none have survived in their original editions, but are extant in Latin or Armenian translations. His best known work is Adversus haereses, considered an excellent exposition of the Gnostic heresy as well as other heretical philosophies. A second treatise, Proof of the Apostolic Preaching, expounds on the Gospels as interpreted through Old Testament prophecies. Only fragments exist of Irenaeus’s other works.