Arianism (Koine Greek: Ἀρειανισμός, Areianismós) is a Christological doctrine that rejects the traditional notion of the Trinity, teaching that Jesus was created by God and is therefore distinct from God. It is named after its proponent Arius (250 or 256 – 336) and is regarded as heretical by most modern mainstream branches of Christianity. Arianism is held by a minority of modern denominations, although some of these groups espouse related doctrines such as Socinianism, and others avoid the term "Arian" because of its historically negative connotations. Modern denominations sometimes associated with the teaching include Jehovah's Witnesses, some churches within the Churches of Christ (among them the movement's founder, Barton W. Stone), and certain Hebrew Roots Christians and Messianic Jews, although many Messianic Jews adhere to Nicene Christianity. The Arian view is also held by The Church of Jesus Christ of Latter-day Saints, although the theology is more distinct in key ways.
It is first attributed to Arius, a Christian presbyter who preached and studied in Alexandria, Egypt, although it developed out of various preexisting strands of Christianity which differed from later Nicene Christianity in their view of Christology. Arian theology holds that Jesus Christ is the Son of God, who was begotten by God the Father with the difference that the Son of God did not always exist but was begotten/made before time by God the Father; therefore, Jesus was not coeternal with God the Father, but nonetheless Jesus began to exist outside time.