The Non-subscribing Presbyterian Church of Ireland derives its name and its liberal and tolerant identity from early 18th century Presbyterian ministers who refused to subscribe at their ordination to the Westminster Confession, a standard Reformed (Calvinist) statement of faith; and who formed, in 1725, the Presbytery of Antrim. A similar phenomenon led to the creation of the Remonstrant Synod of Ulster in 1830. The two bodies created the Non-subscribing Presbyterian Church of Ireland (NSPCI) in 1910. The Synod of Munster became part of the NSPCI in 1935.
Many Non-subscribing Presbyterians keep close contact with the Unitarians and are sometimes identified as such, though they are distinct bodies.