The territory now part of the United States has been inhabited for from 15,000 to 40,000 years, as attested by local evidence. The aboriginal peoples, ancestral to today's American Indians, left no firm monuments on the scale of contemporaneous cultures elsewhere, but both the pueblos of the Southwest and the great mounds of the Mississippi River valley antedate the arrival of the European colonial powers. The original 13 British colonies that became the United States of America in 1776 were just one of several attempts by European powers to build empires in North America. All seized land from the native Indians, who then were usually either assimilated or driven off by superior European weapons. The Spaniards reached Florida as early as 1513 and New Mexico in 1540. The French began their exploration of the Mississippi River valley in 1673. The Russians reached Alaska in 1741.
Of all the colonizers, the British were the most successful. In 1607 Jamestown became the first permanent British settlement in North America and the foundation of the Virginia colony. It was followed 13 years later by the Pilgrim settlement at Plymouth, which was soon dwarfed by the Puritan colony of Massachusetts Bay. Most of New England was settled by Puritans fleeing either the harassment of Charles I or the orthodoxy of Massachusetts Bay. Pennsylvania was given to the Quaker William Penn as payment for a debt, and Maryland, a grant to the Roman Catholic George Calvert, was the first colony to establish religious freedom. The British took New York, New Jersey, and Delaware from the Dutch in 1664, a year after the Carolinas had been granted to eight British noblemen. The 13th colony