Alexandrian theologian, who taught that Jesus as God-the-Son was not of the same substance as God-the-Father, but a created being exalted above all other creatures. This doctrine was discarded in 325, at the First Ecumenical Council of Nicaea, summoned by the Czar Constantine for the purpose of conciliation of religious disputes. Arius was expelled into Illyricum, where he continued with his activities.