The Presbyterian Church in the United States of America (PCUSA) was the first national Presbyterian denomination in the United States, existing from 1789 to 1958. In that year, the PCUSA merged with the United Presbyterian Church of North America, a denomination with roots in the Seceder and Covenanter traditions of Presbyterianism. The new church was named the United Presbyterian Church in the United States of America. It was a predecessor to the contemporary Presbyterian Church (USA). The denomination had its origins in colonial times when members of the Church of Scotland and Presbyterians from Ireland first immigrated to America. After the American Revolution, the PCUSA was organized in Philadelphia to provide national leadership for Presbyterians in the new nation. In 1861, Presbyterians in the Southern United States split from the denomination because of disputes over slavery, politics, and theology precipitated by the American Civil War. They established the Presbyterian Church in the United States, often simply referred to as the "Southern Presbyterian Church". Due to its regional identification, the PCUSA was commonly described as the Northern Presbyterian Church. Despite the PCUSA's designation as a "Northern church", it was once again a national denomination in its later years. Over time, traditional Calvinism played less of a role in shaping the church's doctrines and practices—it was influenced by Arminianism and revivalism early in the 19th century, liberal theology late in the 19th century, and neo-orthodoxy by the mid-20th century. The theological tensions within the denomination were played out in the Fundamentalist–Modernist Controversy of the 1920s and 1930s, a conflict that led to the development of Christian fundamentalism and has historical importance to modern American evangelicalism. Conservatives dissatisfied with liberal trends left to form the Orthodox Presbyterian Church in 1936, and again, another conservative separation in 1973 resulting in the formation of the Presbyterian Church in America (PCA). History Colonial era Early organization efforts (1650–1729) The origins of the Presbyterian Church is the Protestant Reformation of the 16th century. The writings of French theologian and lawyer John Calvin (1509–64) solidified much of the Reformed thinking that came before him in the form of the sermons and writings of Huldrych Zwingli. John Knox, a former Catholic priest from Scotland who studied with Calvin in Geneva, Switzerland, took Calvin's teachings back to Scotland and led the Scottish Reformation of 1560. As a result, the Church of Scotland embraced Reformed theology and presbyterian polity. The Ulster