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 defeat 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. In response, Williams traveled to England to secure a charter for the colony. Return to England and charter matters A Key into the Language of America Williams arrived in London in the midst of the English Civil War. Puritans held power in London, and he was able to obtain a charter through the offices of Sir Henry Vane the Younger, despite strenuous opposition from Massachusetts' agents. His first published book A Key into the Language of America proved crucial to the success of his charter, albeit indirectly. Published in 1643 in London, the book combined a phrase-book with observations about life and culture as an aid to communicate with the Native Americans of New England. In its scope, the book covered everything from salutations to death and burial. Williams also sought to correct the attitudes of superiority displayed by the colonists towards Native Americans: Printed by Gregory Dexter, the book was the first book-length study of a native North American language in the English language. In England, the book was well received by readers who were curious about