Nicene Christianity includes thoseChristian denominations that adhere to the teaching of theNicene Creed,[1] which was formulated[2] at theFirst Council of Nicaea in AD 325 and amended at theFirst Council of Constantinople in AD 381.[3] It encompasses the vast majority of today's Christian churches.
At the time of theFirst Council of Nicaea, the main rival of Nicene Christian doctrine was that ofArianism, which became eclipsed during the 7th century AD with the conversion of theGothic kingdoms to Nicene Christianity. The main points of dissent between the two centered onChristology, or the nature of Jesus' divinity. Nicene Christianity regards Jesus as divine and co-eternal withGod the Father, while Arianism treats him as the first among created beings and inferior to God the Father. Various other Nicene doctrines and beliefs have existed since theearly medieval period, all of which have been consideredheresies.[2]
Religious historians and scholars often define Nicene Christianity as being the first incarnation of thestate church of the Roman Empire that was officially endorsed by the Roman Emperors from 381. According to this definition, the Nicene Church ceased to exist following theCouncil of Chalcedon in 451, which was convened to address Christological disagreements on the human and divine natures of Christ, concluding that Christ had two distinct inseparable natures. Following the council, the Roman Empire establishedChalcedonian Christianity as its official state religion; those churches which held that Christ was of a single nature wereexcommunicated by the Empire and became theOriental Orthodox Churches.[citation needed]
Today, examples of non-Nicene Christian denominations encompass both Protestant and non-Protestantnon-trinitarian groups. Examples of these groups include the majority of theLatter Day Saint movement (with the exception of the Nicene Mormon group known as theCommunity of Christ, formerly known as the Reorganized Church of Jesus Christ of Latter Day Saints),Jehovah's Witnesses, theUnitarian Church of Transylvania,Oneness Pentecostals, among others.[citation needed]
In the most common sense, "mainstream" refers to Nicene Christianity, or rather the traditions which continue to claim adherence to the Nicene Creed.
