The Council of Nicaea
The Arian debate was the impetus for the First Council of Nicaea which met in 325 A.D. Neither Arius nor Athanasius were present at the Council. They would argue with each other afterward. Arianism was repudiated by the Council and the Nicene Creed was formulated. Aside from the Apostles' Creed, it is the most ecumenical creed, finding wide acceptance among Orthodox, Catholic, and Protestant churches. Even churches that do not claim to be "creedal" accept the doctrine of the Nicene Creed.
The question of Christ's divinity was officially settled at Nicaea, even though the debate continued to rage for some time afterward. The question of how Christ's divinity and humanity related to each other in the person of Christ still remained. There were two basic schools of thought. These have been labeled as "Antiochene" and "Alexandrine."
Both sides agreed that God was unchangeable and eternal. The disagreement came over the question of how the immutable and eternal God can be joined to a changeable, historical human being. The Alexadrines (e.g. Clement and Origen) emphasized Jesus' divinity. His humanity must not eclipse his deity. The Antiochenes (e.g. Diodorus and Theodore), on the other hand, emphasized his humanity. Both schools affirmed Christ's two natures; the question was how to understand the relationship between the two.
It is important to note that Antioch and Alexandria were eastern cities, as was Nicaea. The christological and trinitarian debates were primarily eastern in origin. In the west, the church had, what seemed to be, more pressing problems. The western church had its hands full dealing with the barbarian invasions. Western theologians were content with Tertullian's formula which affirmed God was three persons in one substance. Western theologians were content to leave the solution there.
In the east, several theologians attempted to explain the relationship between the two natures of Christ. They were not very successful.
See further Justo Gonzalez, The Story of Christianity, Volume 1.
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I do not seek to understand that I may believe, but I believe in order to understand. For this also I believe, –that unless I believed, I should not understand.-- St. Anselm of Canterbury (1033-1109)