Arian controversy
This conflicted with the Trinitarian faction initially advanced by Athanasius which argued that the Christ was coeternal and consubstantial with God the Father.
Emperor Constantine, through the Council of Nicaea in 325, attempted to unite Christianity and establish a single, imperially approved version of the faith.
Inside the Roman Empire, the Trinitarian faction ultimately gained the upper hand through the Edict of Thessalonica, issued on 27 February AD 380, which made Nicene Christology the state religion of the Roman Empire,[3] and through strict enforcement of that edict.
According to Eusebius's work, The Life of Constantine, the controversy had spread from Alexandria into almost all the African regions, and was considered a disturbance of the public order by the Roman Empire.
By the time Bishop Alexander finally acted against his presbyter, Arius's doctrine had spread far beyond his own see; it had become a topic of discussion—and disturbance—for the entire Church.
"Constantine desired that the church should contribute to the social and moral strength of the empire, religious dissension was a menace to the public welfare.
Hosius was armed with an open letter from the Emperor: "Wherefore let each one of you, showing consideration for the other, listen to the impartial exhortation of your fellow-servant."
[10] Those who upheld the notion that Christ was co-eternal and con-substantial with the Father were led by the young archdeacon Athanasius.
"[14] According to some accounts in the hagiography of Saint Nicholas, debate at the council became so heated that at one point, he slapped Arius in the face.
Ursacius of Singidunum and Valens of Mursa, following the new creed drafted at Sirmium (359), proposed that, "according to the scriptures," the Son was "like the Father."
The council was bitterly divided and procedurally irregular, and the two parties met separately and reached opposing decisions.
[21][22] But Basil of Ancyra and his party, following a (Homoiousian) Creed of Antioch from 341, declared that the Son was of "similar substance" to the Father.
Constantius did not accept this outcome and requested a third council, at Constantinople (359), of both the eastern and western bishops, to resolve the split at Seleucia.
Acacius and Basil of Ancyra, respectively, again proposed the "like the Father" and "similar substance" views, as were explained at Seleucia.
[23][24] After the Council of Constantinople, the homoian bishop Acacius deposed and banished several homoiousian bishops, including Macedonius I of Constantinople, Basil, Eustathius, Eleusius of Cyzicus, Dracontius of Pergamum, Neonas of Seleucia, Sophronius of Pompeiopolis, Elpidius of Satala and Cyril of Jerusalem.
[27] According to Philostorgius, pagans killed George of Laodicea, bishop of Alexandria, allowing Athanasius to reclaim the 'see', or ecclesiastical jurisdiction.
"[43] Their opponents associated the teachings of Marcellus of Ancyra and Photinus of Sirmium with those of Sabellius and Paul of Samosata, which had been widely rejected before the controversy.
