Final answer:
Roger Williams was banished for his views on religious freedom, separation of church and state, and his opposition to the taking of Native American lands, leading him to found Rhode Island, known for its religious tolerance and democratic principles.
Step-by-step explanation:
Roger Williams was banished from the Massachusetts Bay Colony due to his revolutionary beliefs and actions. He challenged the confiscation of Native American land and insisted on complete separation from the Church of England, both of which put him at odds with the existing Puritan leadership. His stance on religious freedom and his view that the state should not have the power to punish individuals for their beliefs were deemed dangerous by the authorities.
Realizing his potential banishment, Williams left before he could be sent to England and went on to found Rhode Island, which became known for its religious tolerance and separation of church and state, contrasting sharply with the intolerance of the Massachusetts Bay Colony.