Arianism

Arianism is the theological teaching attributed to Arius (ca. AD 250–336), a Christian presbyter in Alexandria, Egypt, concerning the relationship of the persons of the Trinity ('God the Father', 'God the Son' (Jesus of Nazareth), and 'God the Holy Spirit') and the precise nature of the Son of God as being a subordinate entity to God the Father. Deemed a heretic by the Ecumenical First Council of Nicaea of 325, Arius was later exonerated in 335 at the regional First Synod of Tyre, and then, after his death, pronounced a heretic again at the Ecumenical First Council of Constantinople of 381. The Roman Emperors Constantius II (337–361) and Valens (364–378) were Arians or Semi-Arians.