Arius
Arius (; Koine Greek: Ἄρειος, 250 or 256–336) was a Libyan presbyter and ascetic, and priest in Baucalis in Alexandria, Egypt. His teachings about the nature of the Godhead in Christianity, which emphasized the God's uniqueness and the Christ's subordination under the Father, and his opposition to what would become the dominant Christology, Homoousian Christology, made him a primary topic of the First Council of Nicaea, which was convened by Emperor Constantine the Great in 325.
After Emperors Licinius and Constantine legalized and formalized the Christianity of the time in the Roman Empire, Constantine sought to unify the newly recognized Church and remove theological divisions. The Christian Church was divided over disagreements on Christology, or, the nature of the relationship between Jesus and God.