In the meantime, the Pequot War had broken out.
Massachusetts Bay asked for Williams' help, which he gave despite his exile, and he became the Bay colony's eyes and ears, and also dissuaded the Narragansetts from joining with the Pequots.
Instead, the Narragansetts allied themselves with the Colonists and helped to crush the Pequots in 1637–38.
The Narragansetts thus became the most powerful Native American tribe in southern New England.

Williams formed firm friendships and developed deep trust among the Native American tribes, especially the Narragansetts.
He was able to keep the peace between the Native Americans and the Colony of Rhode Island and Providence Plantations for nearly 40 years by his constant mediation and negotiation.
He twice surrendered himself as a hostage to the Native Americans to guarantee the safe return of a great sachem from a summons to a court: Pessicus in 1645 and Metacom ("King Philip") in 1671.
Williams was trusted by the Native Americans more than any other Colonist, and he proved trustworthy.

However, the other New England colonies began to fear and mistrust the Narragansetts and soon came to regard the Rhode Island colony as a common enemy.
In the next three decades, Massachusetts, Connecticut, and Plymouth exerted pressure to destroy both Rhode Island and the Narragansetts.
In 1643, the neighboring colonies formed a military alliance called the United Colonies which pointedly excluded the towns around Narragansett Bay.
The object was to put an end to the heretic settlements, which they considered an infection.
In response, Williams traveled to England to secure a charter for the colony.
In the meantime, the Pequot War had broken out. Massachusetts Bay asked for Williams' help, which he gave despite his exile, and he became the Bay colony's eyes and ears, and also dissuaded the Narragansetts from joining with the Pequots. Instead, the Narragansetts allied themselves with the Colonists and helped to crush the Pequots in 1637–38. The Narragansetts thus became the most powerful Native American tribe in southern New England.
Williams formed firm friendships and developed deep trust among the Native American tribes, especially the Narragansetts. He was able to keep the peace between the Native Americans and the Colony of Rhode Island and Providence Plantations for nearly 40 years by his constant mediation and negotiation. He twice surrendered himself as a hostage to the Native Americans to guarantee the safe return of a great sachem from a summons to a court: Pessicus in 1645 and Metacom ("King Philip") in 1671. Williams was trusted by the Native Americans more than any other Colonist, and he proved trustworthy.
However, the other New England colonies began to fear and mistrust the Narragansetts and soon came to regard the Rhode Island colony as a common enemy. In the next three decades, Massachusetts, Connecticut, and Plymouth exerted pressure to destroy both Rhode Island and the Narragansetts. In 1643, the neighboring colonies formed a military alliance called the United Colonies which pointedly excluded the towns around Narragansett Bay. The object was to put an end to the heretic settlements, which they considered an infection. In response, Williams traveled to England to secure a charter for the colony.
Roger Williams