Arianism (âr'ēuniz"um) [key], Christian heresy founded by Arius in the 4th cent. It was one of the most widespread and divisive heresies in the history of Christianity. As a priest in Alexandria, Arius taught (c.318) that God created, before all things, a Son who was the first creature, but who was neither equal to nor coeternal with the Father. According to Arius, Jesus was a supernatural creature not quite human and not quite divine. In these ideas Arius followed the school of Lucian of Antioch.
