• Born year: 0130
  • Born in: TurkeY
  • Death year: 0202
  • Death in: FrancE

Irenaeus (/aɪrəˈniːəs/; Greek: Εἰρηναῖος) (early 2nd century – c. AD 202), referred to by some as Saint Irenaeus, was Bishop of Lugdunum in Gaul, then a part of the Roman Empire (now Lyon, France). He was an early Church Father and apologist, and his writings were formative in the early development of Christian theology. He was a hearer of Polycarp, who in turn was traditionally a disciple of John the Evangelist.Irenaeus' best-known book, Adversus Haereses or Against Heresies (c.