Nontrinitarianism

===Following the Reformation===
{{expand section|1=information on other sects such as Mormonism and Jehovah's Witnesses|date=August 2016}}
By 1530, following the [[Protestant Reformation]], and the [[German Peasants' War]] of 1524–1525, large areas of Northern Europe were Protestant, and forms of nontrinitarianism began to surface among some "[[Radical Reformation]]" groups, particularly [[Anabaptist]]s. The first recorded English antitrinitarian was [[John Assheton]] (1548), an [[Anglican]] priest. The Italian Anabaptist "[[Council of Venice]]" (1550) and the trial of [[Michael Servetus]] (1553) marked the clear emergence of markedly antitrinitarian Protestants. Though the only organised nontrinitarian churches were the [[Polish Brethren]] who split from the Calvinists (1565, expelled from Poland 1658), and the [[Unitarian Church of Transylvania]] (founded 1568). [[Nonconformist (Protestantism)|Nonconformist]]s, [[Dissenter]]s and [[Latitudinarian]]s in Britain were often [[Arian]]s or [[Unitarianism|Unitarians]], and the [[Doctrine of the Trinity Act 1813]] allowed nontrinitarian worship in Britain. In America, Arian and Unitarian views were also found among some [[Millennialist]] and [[Adventism|Adventist]] groups, though the [[American Unitarian Association|Unitarian Church]] itself began to decline in numbers and influence after the 1870s.<ref>''Unitarians face a new age: the report of the Commission of Appraisal.'' American Unitarian Association. ed. Frederick May Eliot, Harlan Paul Douglass – 1936 "Chapter III Church Growth and Decline During the Last Decade. Year Book data permit the calculation of growth or decline in membership for 297 Unitarian churches which existed throughout the last decade and ..."</ref><ref>Charles Lippy (2006), ''Faith in America: Changes, Challenges'', New Directions, p.2. Quote: "However, when the national interest in novel religious forms waned by the mid- nineteenth century, Unitarianism and Universalism began to decline. For the vast majority of religious bodies in America, growth continued unabated."</ref>