What was the primary reason that

The primary reason Roger Williams left the Massachusetts Bay Colony and founded the Rhode Island colony was his belief in the principle of religious freedom and the separation of church and state. Williams felt that the Massachusetts Bay Colony's policy of enforcing strict religious conformity and punishing dissenters was unjust. He advocated for the idea that individuals should have the liberty to practice their own faith without interference from the government or established church authorities. This led him to seek a place where he could practice his beliefs and gather others who shared his views, culminating in the establishment of Rhode Island as a colony that embraced religious tolerance and freedom.