Today is the feast day of St. Irenaeus of Lyon, a 2nd century bishop and theologians in France. He is noted for his role in guiding and expanding Christian communities in the southern regions of present-day France and, more widely, for the development of Christian theology by combating Gnostic interpretations of Scripture as heresy. Included with this post are two videos. The first is an overview of the life of St. Irenaus. The second is a more detailed video on Irenaeus presented by Bishop Barron. Enjoy.His best-known work is Against Heresies (Adversus Haereses) a refutation of gnosticism. To counter the doctrines of the gnostic sects claiming secret wisdom, he offered three pillars of orthodoxy: the scriptures, the tradition handed down from the apostles, and the teaching of the apostles’ successors. Intrinsic to his writing is that the surest source of Christian guidance is the Church of Rome, and he is the earliest surviving witness to regard all four of the now-canonical gospels as essential.