The Puritans who founded Massachusetts Bay Colony were, like the Pilgrims, religious Protestants (both sects “protested” the Anglican church). But while the Pilgrims separated from the church, the Puritans wished to purify it. Their religious movement began in England during the 1500s, and they were influenced by the teachings of reformer John Calvin (1509–1564). They also had strong feelings about government, maintaining that people can only be governed by contract (such as a constitution), which limits the power of a ruler. When King James I (1566–1625) ascended the throne of England in 1603, he was the first ruler of the house (royal family) of Stuart. The Stuart monarchs, particularly James’s successor, King Charles I (1600–1649), tried to enforce absolute adherence to the High Church of Anglicanism and viewed the Puritan agitators as a threat to the authority of the crown.

Persecuted by the throne, groups of Puritans fled England for the New World. One group was granted a corporate charter for the Massachusetts Bay Company (1629). Unlike other such contracts, which provided the framework for establishing colonies in America, this one did not require the stockholders to hold their meetings in England. Stockholders who made the voyage across the Atlantic would become voting citizens in their own settlement; the board of directors would form the legislative assembly; and the company president, Puritan leader John Winthrop (1588–1649), would become the governor. In 1630 they settled in what is today Boston and Salem, Massachusetts, establishing a Puritan Commonwealth. By 1643 more than 20,000 Puritans arrived in Massachusetts, in what is called the Great Migration. Puritans also settled in Rhode Island, Connecticut, and Virginia during the colonial period.