![[Media/Nikea-arius 1.png]] *Icon from a monastery in Greece, representing the Council of Nicaea 325 with Constantine in the center and the condemned Arius in the bottom of the icon.* Constantine defeated his imperial rival in that battle in 312, and in 313 played an influential role in the Edict of Milan, which declared tolerance for Christianity in the Roman Empire. After ending the Tetrarchy and becoming the sole emperor in 324, Constantine convened the Council of Nicaea in 325, to address theological disputes, particularly a debate about the divinity or humanity of Jesus called the Arian controversy. In addition to declaring Arianism a heresy and adopting the Nicene Creed (which is still a central element of Christianity), the council standardized the process for determining the date of Easter and issued twenty canons (church laws) regarding clergy discipline and what to do with those lapsed Christians from Carthage. They were not excluded, but were required to do twelve years of penance before being welcomed back into the community as full members. ![[Media/Old_St_Peter's_Basilica,_Rome,_about_the_year_1450_restored_from_ancient_authorities.jpg]] While the Council of Nicaea was a significant step forward for the legitimacy of the church in Roman society, in 325 christians were still only about 10% to 20% of all Romans. Constantine continued to favor the church, funding churches such as the Basilica of St. Peter in Rome, exempting clergy from taxes, and appointing Christians to high office. But it wasn't until 380 that Emperor Theodosius declared Nicene Christianity the official religion of the empire and banned pagan worship. ----- Next: [[8.6 - Constantinople]] Back: [[8.4 - Constantine]]