The Puritans were a group of English Protestants in the 16th and 17th centuries, including, but not limited to, English Calvinists. Puritanism in this sense was founded by John Calvin from the clergy shortly after the accession of Elizabeth I of England in 1558, as an activist movement within the Church of England.
In modern times, the word 'puritan' is often used to mean 'against pleasure'. Historically, the word was used pejoratively to characterize the Protestant group as extremists, similar to the Cathars of France and, according to Thomas Fuller in his Church History, dated back to 1564. Archbishop Matthew Parker of that time used it and 'precisian' with the sense of the modern .
Puritans were blocked from changing the established church from within, and were severely restricted in England by laws controlling the practice of religion. Their beliefs, however, were transported by the emigration of congregations to the Netherlands (and later to New England), and by evangelical clergy to Ireland (and later into Wales), and were spread into lay society and parts of the educational system, particularly certain colleges of the University of Cambridge. They took on distinctive beliefs about clerical dress and in opposition to the episcopal system, particularly after the 1619 conclusions of the Synod of Dort they were resisted by the English bishops. They largely adopted Sabbatarianism in the 17th century, and were influenced by millennialism.
In alliance with the growing commercial world, the parliamentary opposition to the royal prerogative, and in the late 1630s with the Scottish Presbyterians with whom they had much in common, the Puritans became a major political force in England and came to power as a result of the First English Civil War (1642–46). After the Restoration of 1660 and the 1662 Uniformity Act, almost all Puritan clergy left the Church of England, some becoming nonconformist ministers. The nature of the movement in England changed radically, although it retained its character for a much longer period in New England.
Puritans, by definition, were dissatisfied with the limited extent of the English Reformation, and the Church of England's tolerance of practices which they 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 group piety. Puritans adopted a Reformed theology and, in that sense, were Calvinists (as were many of their earlier opponents), but they also took note of radical criticisms of Zwingli in Zurich and Calvin in Geneva. In church polity, some advocated for separation from all other Christians, in favor of autonomous gathered churches. These separatist and independent strands of Puritanism became prominent in the 1640s, when the supporters of a Presbyterian polity in the Westminster Assembly were unable to forge a new English national church.
The term Puritan, never a formally defined sect or religious division within Protestantism, was used rarely to describe people after the turn of the 18th century. Puritan ideals either became incorporated into the Church of England, such as the formal rejection of Roman Catholicism; fell out of favor, such as the beliefs in demonic possession, or were absorbed into the many Protestant sects that emerged in the late 17th and early 18th centuries in the Americas and Britain. The Congregationalist tradition is one such Protestant denomination that claims descent from the Puritan tradition.