St. Irenaeus of Lyon was a big defender of the Catholic Church's teachings in the 2nd century, pointing out to others the error of their ways.
His efforts have given him a reputation of being a bridge-builder, uniting all Christians under the one roof of the Catholic Church. Recently, Pope Francis announced that Irenaeus will be named a Doctor of the Church, with the title "Doctor of Unity."
Below is a prayer asking the intercession of St. Irenaeus for Christian unity, a unity established through peaceful dialogue.