Arianism

Arianism is a historical Christian theological position associated with Arius, an Alexandrian presbyter of the early 4th century. It centers on the nature of the Son of God and the relationship between the Father and the Son. Arius taught that the Son is a distinct, subordinate, and created being who is not co-eternal with the Father. According to this view, there was a time when the Son did not exist, and the Word was brought into existence by the Father. While the Son shares in divine qualities, he is not of the same essence as the Father.

The movement sparked intense controversy within early Christianity, leading to a decisive confrontation at the First Council of Nicaea in 325. The council condemned Arianism as heterodox and produced the Nicene Creed, which affirmed that the Son is homoousios with the Father, meaning of the same essence. This marked a defining moment in the development of Christological doctrine in the Roman Empire, though various forms of Arian or semi-Arian thought persisted in different communities.

In the decades and centuries after Nicaea, Arian ideas gained influence at times, particularly in the eastern half of the empire under emperors such as Constantius II. The theological landscape remained contested, and the term “Arian” came to denote a spectrum of Christological positions that emphasized the Son’s created or subordinate status. The Council of Constantinople in 381 reaffirmed the Nicene formula and helped reduce Arian influence within the Roman Church, though Arianism persisted among several non-Roman Christian groups, including some Germanic peoples such as the Goths and Vandals, for a period. By late antiquity, Arianism had largely declined in mainstream Christianity, though it remains a significant subject in the study of early Christian doctrinal development.