Massasoit Ousamequin lived in Montaup, a Pokanoket village at the site of what is now the town of Bristol, Rhode Island. He held the allegiance of a number of lesser Pokanoket sachems.
Outbreaks of smallpox had devastated the Pokanokets, and Massasoit sought an alliance with the English against the neighboring Narragansetts who controlled an area west of Narragansett Bay in present-day Rhode Island. Massasoit forged critical political and personal ties with colonial leaders William Bradford, Edward Winslow, Stephen Hopkins, John Carver, and Myles Standish, ties which grew out of a negotiated peace treaty on March 22, 1621. The alliance ensured that the Wampanoags remained neutral during the Pequot War in 1636.
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.
There was some tension between Massasoit and the colonists when they refused to give up Squanto whom Massasoit believed to have betrayed him. This, however, was resolved in March 1623 when Massasoit was gravely ill and Edward Winslow nursed him back to health. After his recovery, Winslow reports that Massasoit said, "the English are my friends and love me... whilst I live I will never forget this kindness they have showed me." In return for their kindness, Massasoit warned the Plymouth colonists of a plot against them. He had learned that a group of influential Massachusett warriors intended to destroy both the Wessagusset and Plymouth colonies, and he warned the Pilgrims in time.
The alliance came under minor tension in later years, as the colonists needed to expand into new lands in order to support their growing colony. Massasoit sold a tract of land fourteen miles square to Myles Standish and others of Duxbury in 1649 to alleviate tension and maintain the peace between his people and the colonists. The sale took place atop Sachem Rock, an outcropping on the Sawtucket River in what is now East Bridgewater, Massachusetts. The site is listed on the National Register of Historic Places.
Massasoit had five children: "Moanam", or Wamsutta, who was born sometime between 1621 and 1625; Pometecomet, Metacomet, or Metacom; a third son, Sonkanuchoo; and two daughters, one named Amie and one given the Christian name Sarah. Sarah was married to James Covell so it is possible her name was documented as Aquinnah Mary Covell (married James Covell). Soon after the death of Massasoit, Wamsutta and Pometecomet went to Plymouth and requested the Pilgrims to give them English names. The court named them Alexander and Philip. Wamsutta (Alexander), the eldest, became sachem of the Pokanoket on the death of his father. Wamsutta died within a year, and his brother Metacom (Philip) succeeded him in 1662.
For nearly forty years, the Wampanoags and the English of Massachusetts Bay Colony maintained peace until Massasoit's death. Roger Williams was banished from the Massachusetts colony and was taken in by Massasoit for several weeks. Massasoit was humane and honest, never violated his word, and constantly endeavored to imbue his people with a love of peace. He kept the Pilgrims advised of any warlike designs toward them by other tribes.
It is unclear when Massasoit died. Some accounts claim that it was as early as 1660; others contend that he died as late as 1662. He was anywhere from 80 to 90 at the time. When Massasoit died, his son Wamsutta (Alexander) became his successor, but Wamsutta also died in 1662 and Metacom (Philip) succeeded him. Amie, wife of Tispaquin, was the only one of Massasoit's five children to survive King Philip's War in 1676.
The half century of peace that Massasoit so assiduously maintained collapsed soon after his death. Wamsutta broke away from his father's diplomacy and began to form an alliance with Connecticut Colony. He died suddenly within a year of his succession in 1662. Massasoit's second son Metacom became sachem of the Pokanokets and chief sachem of the Greater Wampanoag Confederacy. Metacom (also known as Philip) believed that Wamsutta had been murdered at the hands of the English. Wamsutta's death was one of the factors that eventually led to King Philip's War, one of the bloodiest wars in American history.
Roger Williams fled the Massachusetts Bay Colony to avoid arrest and deportation and stayed the winter of 1635–36 with Massasoit, who gave him land along the Seekonk River the following spring. Governor Winslow of Plymouth Colony advised Williams to move his settlement to the other side of the river because his current location was within the bounds of Plymouth Colony. Williams did so and founded Providence Plantation which later became the state of Rhode Island.
Statues of Massasoit by sculptor Cyrus E. Dallin stand near Plymouth Rock, outside the Utah State Capitol building, on the campus of Brigham Young University, at the Springville Museum of Art in Springville, Utah, and in Kansas City, Missouri at the corner of Main Street and Emanuel Cleaver II Blvd. In Massachusetts, both Massasoit Community College and Massasoit State Park are named for him.
The Pokanoket chief appeared in "The Mayflower Voyagers", a 1988 episode of the Peanuts television miniseries This is America, Charlie Brown.
At the beginning of the 1995 film adaptation of Nathaniel Hawthorne's Scarlet Letter, Massasoit dies and the tribe cremates his corpse. His son, Metacomet succeeds him as the tribe's new chief.
Massasoit was referred to as "Yellow Feather" in the 2013 novel Ghost Hawk by Susan Cooper.
The 2017 novel "My Father's Kingdom" by James W. George depicts the legacy of Massasoit and the events leading to King Philip's War