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Who was Arius of Alexandria?

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Christology The Transfiguration, the nature of Jesus as the Son of God being revealed to the apostles Peter, James, and John, mosaic icon, early 13th century; in the Louvre, Paris.

Arius (c. 250–336) was a Christian priest and scholar based in Alexandria whose theological teachings sparked the Arian controversy, one of the most significant disputes in early Christianity.12

Arius proposed a Christological model that emphasized strict monotheism. He argued that the Son was a created being who had a beginning and was not of the same essence or substance as God the Father. This doctrine, known as Arianism, maintained that because God is unique, immutable, and self-existent, the Son—who is mutable and finite—must be a creature.123

His views were formally denounced as heresy at the Council of Nicaea in 325, where the church affirmed that Christ was of the same substance (homoousios) as the Father. Despite this condemnation, Arius remained a polarizing figure with significant support until his death in Constantinople. His teachings continued to influence various theological movements throughout history, including later Unitarian thought.13