What other Christians are there other than Trinitarian?
Some Christian traditions either reject the doctrine of the Trinity or consider it unimportant. Persons and groups espousing this position generally do not refer to themselves as “Nontrinitarians”. They can vary in both their reasons for rejecting traditional teaching on the Trinity, and in the way they describe God.
Nontrinitarian groups:
Since Trinitarianism is central to so much of church doctrine, nontrinitarians were mostly groups that existed before the Nicene Creed was codified in 325 or are groups that developed after the Reformation, when many church doctrines came into question.
In the early centuries of Christian history Adoptionists, Arians, Ebionites, some Gnostics, Marcionites, and others held nontrinitarian beliefs. The Nicene Creed raised the issue of the relationship between Jesus’ divine and human natures. Monophysitism (“one nature”) and monothelitism (“one will”) were early attempts, considered heretical by trinitarians, to explain this relationship.
During more than a thousand years of Trinitarian orthodoxy, formal nontrinitarianism, i.e., a doctrine held by a church, group, or movement, was rare, but it did appear. For example, among the Cathars of the 13th century. The Protestant Reformation of the 1500s also brought tradition into question. At first, nontrinitarians were executed (such as Servetus), or forced to keep their beliefs secret (such as Isaac Newton). The eventual establishment of religious freedom, however, allowed nontrinitarians to more easily preach their beliefs, and the 19th century saw the establishment of several nontrinitarian groups in North America and elsewhere. These include
Christadelphians, Jehovah’s Witnesses, and
Unitarians. Some
Messianic groups are also nontrinitarian. Servetus heavily influenced the theology of
Emanuel Swedenborg; the church founded on his writings is a small but influential nontrinitarian movement. Some groups espousing Binitarianism such as the
Living Church of God claim that Binitarianism was the majority view of those that professed Christ in the second century.
Twentieth-century nontrinitarian movements include
Iglesia ni Cristo, Most Holy Church of God in Christ Jesus, and the
Unification Church. Nontrinitarian groups differ from one another in their views of Jesus Christ, depicting him variously as a divine being second only to God the Father (e.g., Jehovah’s Witnesses), as Yahweh of the Old Testament in human form, as God (but not eternally God), as Son of God but inferior to the Father (versus co-equal), as a prophet, or simply as a holy man.
Oneness Pentecostals deny traditional Trinitarian doctrine, while affirming their belief that God took on flesh in the man Jesus Christ. Like Trinitarians, Oneness adherents believe that Jesus Christ is fully God and fully man. However, whereas Trinitarians believe that “God the Son” (a being whose existence is denied in Oneness theology), the eternal second person of the Trinity, became man, Oneness adherents hold that the one and only true God—who manifests himself in any way he chooses, including as Father, Son and Holy Spirit—became man. Oneness believers view “Father”, “Son” and “Holy Spirit” as titles, reflecting different manifestations of the one true God in the universe. Oneness Pentecostals are regarded by orthodox Christians as subscribing to the heresy of Modalism, teaching that God displayed himself in the Old Testament as Father, in the Gospels as the Son, and after the Ascension as the Holy Spirit, which is not the orthodox doctrine of three distinct and eternal Persons in one divine essence. Rather, Oneness teaches that there is only one being, revealing himself in different ways.
en.wikipedia.org/wiki/Trinity
I bolded the churches which do not accept Trinitarianism. When I was reading this I read that Newton did not believe in Trinitarianism - just a little fact that might be of interest.
