More on St. Irenaeus from Orthodox wiki:
The holy and glorious, right-victorious Hieromartyr Irenaeus of Lyons (c. 130-202) was bishop of Lugdunum in Gaul, which is now Lyons, France. His writings were formative in the early development of Christian theology. He was a disciple of Polycarp of Smyrna, who himself was a disciple of the Apostle John the Theologian. His feast day is August 23.