Saint Irenaeus (Greek: Ειρηναίος), (b. 2n century; d. c 200) was bishop of Lugdunum in Gaul, now Lyons, France. He was an early church father and apologist, and his writings were formative in the early development of Christian theology. He was a disciple of Polycarp of Smyrna, who was said to be a disciple of John the Evangelist.