Congregational polity in the context of "United Church of Christ"

Reformed Christianity, also called Calvinism, is a major branch of Protestantism that began during the 16th-century Protestant Reformation. In the modern day, it is largely represented by the Continental Reformed, Presbyterian, and Congregational traditions, as well as parts of the Anglican (known as "Episcopal" in some regions), Baptist and Waldensian traditions, in addition to a minority of persons belonging to the Methodist faith (who are known as Calvinistic Methodists).

Reformed theology emphasizes the authority of the Bible and the sovereignty of God, as well as covenant theology, a framework for understanding the Bible based on God's covenants with people. Reformed churches emphasize simplicity in worship. Several forms of ecclesiastical polity are exercised by Reformed churches, including presbyterian, congregational, and some episcopal. Articulated by John Calvin, the Reformed faith holds to a spiritual (pneumatic) presence of Christ in the Lord's Supper.

The Puritans were English Protestants in the 16th and 17th centuries who sought to rid the Church of England of what they considered to be Roman Catholic practices, maintaining that the Church of England had not been fully reformed and should become more Protestant. Puritanism played a significant role in English and early American history, especially in the Protectorate in Great Britain, and the earlier settlement of New England.

Puritans were dissatisfied with the limited extent of the English Reformation and with the Church of England's toleration of certain practices associated with the Catholic Church. They formed and identified with various religious groups advocating greater purity of worship and doctrine, as well as personal and corporate piety. Puritans adopted a covenant theology, and in that sense they were Calvinists (as were many of their earlier opponents). In church polity, Puritans were divided between supporters of episcopal, presbyterian, and congregational types. Some believed a uniform reform of the established church was called for to create a godly nation, while others advocated separation from, or the end of, any established state church entirely in favour of autonomous gathered churches, called-out from the world. These Separatist and Independents became more prominent in the 1640s, when the supporters of a presbyterian polity in the Westminster Assembly were unable to forge a new English national church.