New England Confederation is established in Boston.

The pact, primarily a mutual defense alliance against the Native Americans, Dutch, and French, is signed in Boston. Its members include Massachusetts Bay, Plymouth, Connecticut (Hartford), and New Haven. The first union of any of the British Colonies, it also includes boundary and trade provisions. It was promoted by John Winthrop, and, according to Mark Peterson, “shifted the center of Indian diplomacy and negotiations to Boston.” The pact goes into effect when representative meet in Hartford, Connecticut, on September 17, 1643. It is revived during King Philip’s War and dissolved when the Massachusetts Charter is revoked in 1768. John Quincy Adams calls it a model for the North American Confederacy of 1774.