Massasoit (Ousamequin) was born circa 1581 in Montaup, a Pokanoket village at the site of today's Warren and Bristol, Rhode Island. He held the allegiance of seven lesser Wampanoag sachems. Massasoit visited Plymouth in 1621 and negotiated a treaty guaranteeing the English their security in exchange for their alliance against the Narragansett. Massasoit actively sought the alliance since two significant outbreaks of smallpox brought by the English had devastated the Wampanoag during the previous six years.

He was commonly known as Massasoit, but he was called by many other names, including: Ousamequin, Woosamequin, Asuhmequin, Oosamequen, Osamekin, Owsamequin, Owsamequine, and Ussamequen

According to English sources, Massasoit prevented the failure of Plymouth Colony and the almost certain starvation that the Pilgrims faced during the earliest years of the colony's establishment. Moreover, Massasoit forged critical political and personal ties with the colonial leaders, Stephen Hopkins, Edward Winslow and William Bradford which culminated in a negotiated peace treaty on March 22, 1621. For both the burgeoning colony and the Wampanoag, Massasoit's alliance insured that the Wampanoag remained neutral during the Pequot War in 1636. Unfortunately, the peaceful relationship that Massasoit had worked so diligently to create and protect had unforseen dire consequences for the Wampanoag.