St. Irenaeus, born at Smyrna in Asia Minor, was a pupil of the Martyr St. Polycarp, Bishop of that city, and himself a favorite disciple of St. John the Evangelist. Later he became Bishop of Lyons in Gaul, where, with many other Christians, he was put to death for the Faith , 202. In his writings, many of which are still extant, St. Irenaeus bears eloquent testimony to the primary in the Church of St. Peter’s See.

His words are memorable: “It is necessary that the whole Church – that is to say, all the faithful scattered throughout the world – be in agreement with this Church by reason of her primacy for the Apostolic tradition was ever preserved in her.”
(Adapted from Fr. Butler’s Lives of the Saints)