It ought to be well-known that one of the reasons that the Pilgrims came to this country was for religious freedom. After much persecution, they came to this country to worship according to their conscience and interpretation of Scripture.

What is not well-known however is that those first colonies sought freedom for themselves only. They instituted their own “state churches”. Residents of those colonies were required to practice the Puritan version of Christianity.
Even in this country there was not true religious freedom. One of the primary victims of this were the Baptists. Baptists in England in 1614 had declared, "The magistrate is not by virtue of his office to meddle with religion, this or that form of religion, or doctrine; but to leave Christian religion free, to every man's conscience, and to handle only civil transgressions."

Meanwhile a boy named Roger Williams grew up near the plaza where Puritans, who were seeking to reform the Church of England were burned, pilloried, mutilated, whipped and imprisoned. In Europe, some Baptists were drowned for their belief in believer’s baptism by immersion, the method being intentionally ironic.
Roger Williams followed the Puritans to the Massachusetts Bay Colony to minister among those who had themselves been persecuted. But when he was called to be a pastor at a church in Salem he discovered that people were not free to worship God as they chose there either. His preaching against this got him in trouble. He also argued that Indians should be paid for their land. This kind of talk made him a heretic and a threat.

Williams preached that “there was never civil state in the world that ever did or ever shall make good work of it, with a civil sword in spiritual matters.” He was labeled a rebel. Williams quoted the teachings of Jesus who said, “My Kingdom is not of this world,” and “Give to Caesar what is Caesar and to God what is God’s.” Williams argued that the Government should stay out of religion completely.

Authorities in Boston made a law declaring that everyone must swear an oath affirming the right of the magistrates to rule in religion. Williams was convicted of holding dangerous opinions. When Williams got word that the Governor had ordered that 15 soldiers kidnap Williams and ship him back to England, Williams said goodbye to his wife and newborn child and fled into the wilderness. He found refuge with the Indians.

Along with other persecuted Christians, Williams purchased land from the Indians and named it “Providence.” Those who believed in baptism of believers as opposed to infants were banished by the Massachusetts Government in 1644. The Baptists fled from Massachusetts to Providence, Rhode Island. There Roger Williams founded the first Baptist church in America. People with different beliefs than his also fled there and he protected their right to worship as they chose.

Williams’ colony was an experiment in Religious Liberty. He opposed forcing anyone to comply with Christianity or any form of state religion. He believed that people should profess faith in Christ according to their own conscience and will, not by force.

For More Info - Of course, you can always Google "Roger Williams". I would also encourage you to google "Baptists" and "persecution". You'll find that Baptists endured much persecution in this country. This is part of the reason they were such staunch advocates of the seperation of church and state.

Williams' own words

We have Roger Williams and Baptists to thank for the ideas that led to the First Amendment's guarantee of freedom for religion.

Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof