Congregationalist churches practice a congregationalist form of government, some of which trace their descent from the Congregational Church. The Congregational Church is a family of denominations of Christian Protestantism which arose from the Nonconformist religious movement in England, during the Puritan reformation. In Great Britain, the early congregationalists were called separatists or independents, and some congregationalists still call themselves "Independents" there. The Congregational Church was formed on a theory of union published by Robert Brown, in 1592. They are the Pilgrims of Plymouth Rock, and the Puritans of the Massachusetts Bay Colony, which were organized in union by the Cambridge Platform in 1648.
There are difficulties identifying such a specific beginning, because given its distinguishing commitment to the complete autonomy of the local congregation, congregationalism is more easily identified as a movement rather than a single denomination. The idea that each distinct congregation fully constitutes the visible Church can be traced to John Wyclif and the Lollard movement which followed after Wyclif was removed from teaching authority in the Roman Catholic Church. The early Congregationalists shared with Anabaptist theology the ideal of a pure church, which made adult conversion experience important for full membership in the church, unlike other Reformed churches. As such, the Congregationalists were a reciprocal influence on the Baptists, differing from them in that they counted the children of believers in some sense members of the church unlike the Baptists, because of baptism.
Congregationalists that settled in the Massachusetts Bay Colony, had John Cotton as their most influential leader beginning in 1633. Cotton's writings persuaded the Calvinist theologian John Owen (church leader) to separate from the Presbyterian church, after which he became very influential in the development of Congregationalist theology and ideas of church government. Jonathan Edwards, considered by some to be the most important theologian ever produced in America, was a Congregationalist. The history of Congregationalist churches in the United States is closely intertwined with that of the Presbyterian church, especially in New England where Congregationalist influence spilled over into the Presbyterian church. The first colleges and universities in America, including Harvard, Yale, Dartmouth, Williams, Bowdoin, Middlebury and Amherst, all were founded by the Congregationalists.
Without higher courts to ensure doctrinal uniformity among the congregations, Congregationalists have been more diverse than other Reformed churches. Despite the efforts of Calvinists to maintain the dominance of their system, the Congregationalist churches, especially in New England, gradually gave way to the influences of Arminianism, unitarianism, and transcendentalism. Thus the Congregationalist churches were at the same time the first example of the American theocratic ideal and also the seed-bed from which American liberal religion and society arose.