Most of these men were linked by friendship, business or marriage to the Rainborowes, a charismatic clan of English merchant-mariners, pioneers and visionaries who moved back and forth between the Old World and the New in the 1630s and 1640s.

Stephen Winthrop — the son of Gov. John Winthrop of the Massachusetts Bay Colony and a revolutionary who was once described as “a great man for soul liberty” — married Judith Rainborowe, the daughter of Thomas’s brother William. (Winthrop’s father later married Judith’s sister — which, by my reckoning, made the governor both grandfather and uncle to Stephen’s children.) The younger Winthrop decided he couldn’t stand on the sidelines in the colonies when there was a righteous fight in England; he enlisted as a captain in the Parliamentary Army and never returned to America.

Nehemiah Bourne, a Boston shipbuilder, had once been the Rainborowes’ neighbor in London; he too sailed back to fight the crown. Israel Stoughton, who captained the Dorchester militia in the Pequot wars of the 1630s, was a friend of William’s. William himself sold his farmstead in Charlestown to return to England, and Bourne and Stoughton served as officers in the Parliamentary Army under Thomas, whose regiment was packed with colonists. They were with him when he launched the daring amphibious assault on a Royalist garrison in the east of England in 1644 that made these “New-England men” famous all over the country.

The interesting thing about these colonists was their radicalism, their revolutionary fervor. They were Puritans — but they were more than that. They were merchant-venturers, looking for new markets and business opportunities. They were more than that, too. They were idealists, who went to extraordinary lengths and traveled extraordinary distances to fight for the chance to build a fairer society.

These were the men who, when the Parliamentarians had all but won the war and Charles I was imprisoned, pressed Oliver Cromwell and the other Roundhead grandees to sweep away the old order. To change the world. William Rainborowe asserted that there could be no compromise when it came to “the rights and freedoms of the people.” Thomas, who was greatly influenced by the radical colonists in his regiment, hoped the new regime would at least extend the limited male suffrage that was being adopted throughout the New England colonies. But he also pushed hard for the grandees to take it further and grant the vote to all men — something that wouldn’t be achieved in Britain for another 270 years.