The Congregational churches trace their origins to sixteenth-century England, where they were one part of a large and diverse effort to reform the Church of England. After King Henry VIII parted ways with the Roman Catholic Church over his marriage problems, the Anglican Church, as it was also called, kept the forms of Catholicism — the celebration of the Mass, ceremonial "vestments" for the clergy, and the hierarchy of archbishops and bishops — but under the authority of the English king rather than the Pope.
What began as a political change, however, ended up forever changing the landscape of religion in Great Britain and the United States.
The dissenters opposing Church of England were known as "Puritans," at the time a derogatory reference to their uncompromising zeal for simplicity in worship and church organization. They preferred to call themselves "the Reformed," people following the teaching and practice of the Protestant Reformer John Calvin.
The first Congregationalists were Independents, Puritans who believed each church should be a gathering of believers joined together under a covenant agreement, and with the power to choose their own minister. Beyond that, they disagreed about the likelihood of reforming the Church of England and the need for believers to be separated from its corrupting influences.
(Information on this post is from the resources of the Congregational Library on Boston’s Beacon Hill. www.congregationallibrary.org )