ABSTRACT

In the decade following his Decennalia, the political alliance and religious agreement between Constantine and Licinius would crumble, and the two emperors would struggle for supremacy in the Roman world. First, they quarreled over the appointment of a Caesar in Italy, and fought two battles by which Constantine gained control of the Illyrian and Balkan provinces (316-17). Then, they carried on a “cold war” over religion, with Constantine expanding his support for the Christian Church and Licinius affirming his loyalty to the pagan cults. Finally, a campaign against barbarians in Licinian territory by Constantine and a persecution of Christians in the east by Licinius ignited a “holy war” in which Constantine and the Christian cause triumphed over Licinius and the pagan gods (323-24). In the aftermath of his victory, Constantine would proclaim Christianity the favored religion in the Roman Empire, and would extend his imperial beneficence to the eastern Church. When he found that the eastern clergy were divided over the definition of the Deity and the celebration of Easter, the pious emperor climaxed his political triumphs by summoning an Ecumenical Council of the Catholic Church, and by uniting its episcopal leaders around a definitive creed for the Christian faith and a common day for the Easter festival (325).1