https://en.wikipedia.org/wiki/NontrinitarianismNontrinitarianism is a form of Christianity that rejects the mainstream Christian doctrine of the Trinity—the teaching that God is three distinct hypostases or persons who are coeternal, coequal, and indivisibly united in one being, or essence (from the Greek ousia). Certain religious groups that emerged during the Protestant Reformation have historically been known as antitrinitarian, but are not considered Protestant in popular discourse due to their nontrinitarian nature.
According to churches that consider the decisions of ecumenical councils final, Trinitarianism was definitively declared to be Christian doctrine at the 4th-century ecumenical councils,[1][2][3] that of the First Council of Nicaea (325), which declared the full divinity of the Son,[4] and the First Council of Constantinople (381), which declared the divinity of the Holy Spirit.[5]
In terms of number of adherents, nontrinitarian denominations comprise a minority of modern Christianity. The largest nontrinitarian Christian denominations are The Church of Jesus Christ of Latter-day Saints ("Mormons"), Oneness Pentecostals, Jehovah's Witnesses, La Luz del Mundo and the Iglesia ni Cristo, though there are a number of other smaller groups, including Christadelphians, Christian Scientists, Dawn Bible Students, Living Church of God, Assemblies of Yahweh, Israelite Church of God in Jesus Christ, Members Church of God International, Unitarian Universalist Christians, The Way International, The Church of God International, and the United Church of God.[6]
Nontrinitarian views differ widely on the nature of God, Jesus, and the Holy Spirit. Various nontrinitarian philosophies, such as adoptionism, monarchianism, and subordinationism existed prior to the establishment of the Trinity doctrine in AD 325, 381, and 431, at the Councils of Nicaea, Constantinople, and Ephesus.[7] Nontrinitarianism was later renewed by Cathars in the 11th through 13th centuries, in the Unitarian movement during the Protestant Reformation, in the Age of Enlightenment of the 18th century, and in some groups arising during the Second Great Awakening of the 19th century.
The doctrine of the Trinity, as held in mainstream Christianity, is not present in the other major Abrahamic religions.