Alexander had subsequently excommunicated Arius, who had begun to elicit the support of many bishops who agreed with his position.
Support for Arius from powerful bishops like Eusebius of Caesarea and Eusebius of Nicomedia further illustrate the extent to which other Christians in the Empire share Arius' subordinationist Christology.
Arianism affirms that Christ is not truly divine but a created being.
Arius' basic premise is the uniqueness of God, who is alone self-existent and immutable; the Son, who is not self-existent, cannot be God.
The Godhead, because it is unique,cannot be shared or communicated, so the Son cannot be God.
Because the Godhead is immutable, the Son, who is mutable, being represented in the Gospels as subject to growth and change, cannot be God.
The Son must, therefore, be deemed a creature who has been called into existence out of nothing and has had a beginning.
Moreover, the Son can have no direct knowledge of the Father since the Son is finite and of a different order of existence.
Arius' teaching according to its opponents, reduces the Son to a demigod, reintroduces polytheism (since worship of the Son is not abandoned), and undermines the Christian concept of redemption since only he who was truly God could be deemed to have reconciled man to the Godhead.
Hosius, sent in 324 by Constantine as imperial emissary to the East to settle the Arian dispute, convokes a synod at Alexandria of Egyptian bishops.
