Congregationalism is a Protestant, Reformed (Calvinist) tradition in which churches practice congregational government; where each congregation independently and autonomously runs its own affairs.

Reformed Christianity, also called Calvinism, is a major branch of Protestantism that began during the sixteenth-century Protestant Reformation, a schism in the Western Church. In the modern day, it is largely represented by the Continental, Presbyterian, and Congregational traditions, as well as parts of the Anglican and Baptist traditions.