As a Separatist, Williams considered the Church of England irredeemably corrupt and believed that one must completely separate from it to establish a new church for the true and pure worship of God.
The Salem church was also inclined to Separatism, and they invited him to become their teacher.
The leaders in Boston vigorously protested, and Salem withdrew its offer.
As the summer of 1631 ended, Williams moved to Plymouth Colony where he was welcomed, and he informally assisted the minister there.
He regularly preached and, according to Governor William Bradford, "his teachings were well approved".

After a time, Williams decided that the Plymouth church was not sufficiently separated from the Church of England.
Furthermore, his contact with the Narragansett Indians had caused him to question the validity of the colonial charters that did not include legitimate purchase of Indian land.
Governor Bradford later wrote that Williams fell "into some strange opinions which caused some controversy between the church and him".
In December 1632, Williams wrote a lengthy tract that openly condemned the King's charters and questioned the right of Plymouth to the land without first buying it from the Native Americans.
He even charged that King James had uttered a "solemn lie" in claiming that he was the first Christian monarch to have discovered the land.
Williams moved back to Salem by the fall of 1633 and was welcomed by Rev. Samuel Skelton as an unofficial assistant.
As a Separatist, Williams considered the Church of England irredeemably corrupt and believed that one must completely separate from it to establish a new church for the true and pure worship of God. The Salem church was also inclined to Separatism, and they invited him to become their teacher. The leaders in Boston vigorously protested, and Salem withdrew its offer. As the summer of 1631 ended, Williams moved to Plymouth Colony where he was welcomed, and he informally assisted the minister there. He regularly preached and, according to Governor William Bradford, "his teachings were well approved".
After a time, Williams decided that the Plymouth church was not sufficiently separated from the Church of England. Furthermore, his contact with the Narragansett Indians had caused him to question the validity of the colonial charters that did not include legitimate purchase of Indian land. Governor Bradford later wrote that Williams fell "into some strange opinions which caused some controversy between the church and him". In December 1632, Williams wrote a lengthy tract that openly condemned the King's charters and questioned the right of Plymouth to the land without first buying it from the Native Americans. He even charged that King James had uttered a "solemn lie" in claiming that he was the first Christian monarch to have discovered the land. Williams moved back to Salem by the fall of 1633 and was welcomed by Rev. Samuel Skelton as an unofficial assistant.
Roger Williams