Constantine had defeated Lucinius in his war for the Eastern Empire and chose the city of Byzantium to be his capital in 323 AC. Constantine recognized Christianity as an official religion of the Empire, in an attempt to appease the Eastern Empire. But very soon, differences among Christians broke out over determining the relationship between members of the Holy Trinity and wars broke out again, this time religious.
Constantine held a forum in Nikaia in 325 AC to bridge differences between Arius and Bishop Athanasius of Alexandria. The consequences of the forum were disastrous because, initially Arius went into exile and, then Athanasius. These actions sowed divisions among the Eastern churches and sparked a conflict between the state that wanted to control the church and the church that claimed the old privileges of ancient pagan temples.