Irenaeus (/ɪrɪˈneɪəs/; Greek: Εἰρηναῖος Eirēnaios; c. 130 – c. 202 AD) was a Greek bishop 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 heterodox or Gnostic interpretations of Scripture as heresy and defining the Catholic and Orthodox doctrines of the Apostolic Churches. Originating from Smyrna, he had seen and heard the preaching of Polycarp, who in turn was said to have heard John the Evangelist, and thus was the last-known living connection with the Apostles.