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). Nonconformists, Dissenters and Latitudinarians in Britain were often Arians or 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 Adventist groups, though the Unitarian Church itself began to decline in numbers and influence after the 1870s.[50][51]