Estimated Reading Time: 2 minutesIrenaeus of Lyon, Against Heresies, disciple of Polycarp, Smyrna, Quartodeciman controversy, Irenaeus, Irenaeus of Lyon, Against Heresies, Polycarp, Smyrna, Izmir, Gnosticism, Apostle John, early Church Fathers, Quartodeciman controversy, apostolic tradition, Seven Churches, early Christianity, Christian history