John M. Barry is an internationally recognized and widely praised historian. He is something of a renaissance man, as can be seen in his biography: http://www.johnmbarry.com/
A February 5, 2012 review of Barry's book, ROGER WILLIAMS AND THE CREATION OF THE AMERICAN SOUL, includes the following text, which sums up as well as any source I know, Williams' commitment to the principle of separation of church and state"
<<<A Puritan's `War Against Religion.'
In January, while conservative Christians and GOP presidential candidates were charging that "elites" have launched "a war against religion," a federal court in Rhode Island ordered a public school to remove a prayer mounted on a wall because it imposed a belief on 16-year-old Jessica Ahlquist. The ruling seems particularly fitting because it was consistent not only with the 1st Amendment but with the intent of Roger Williams, who founded Rhode Island expressly to provide religious liberty and who called such forced exposure to prayer "spiritual rape."
As Williams' nearly 400-year-old comment demonstrates, the conflict over the proper relationship between church and state is the oldest in American history. The 1st Amendment now defines this relationship, but understanding the full meaning of the amendment requires understanding its history, for the amendment was a specific response to specific historical events and was written with the recognition that freedom of religion was inextricably linked to freedom itself.
The church-state conflict began when Puritans, envisioning a Christian nation, founded what John Winthrop called "a citty upon a hill" in Massachusetts, and Williams rejected that vision for another: freedom. He insisted that the state refrain from intervening in the relationship between humans and God, stating that even people advocating "the most Paganish, Jewish, Turkish, or Antichristian consciences and worships" be allowed to pray — or not pray — freely, and that "forced worship stinks in God's nostrils."
Yet Williams was no atheist. He was a devout Puritan minister who, like other Massachusetts Puritans, fled religious persecution in England. Upon his arrival in 1631 he was considered so godly that Boston Puritans had asked him to lead their church. He declined — because he considered their church insufficiently pure.
Reverence for both Scripture and freedom led Williams to his position. His mentor was Edward Coke, the great English jurist who ruled, "The house of every one is as his castle," extending the liberties of great lords — and an inviolate refuge where one was free — to the lowest English commoners. Coke pioneered the use of habeas corpus to prevent arbitrary imprisonment. And when Chancellor of England Thomas Egerton said, "Rex est lex loquens; the king is the law speaking," and agreed that the monarch could "suspend any particular law" for "reason of state," Coke decreed instead that the law bound the king. Coke was imprisoned — without charge — for his view of liberty, but that same view ran in Williams' veins.
Equally important to Williams was Scripture. Going beyond the "render unto Caesar" verse in the New Testament, he recognized the difficulty in reconciling contradictory scriptural passages as well as different Bible translations. He even had before him an example of a new translation that served a political purpose. King James had disliked the existing English Bible because in his view it insufficiently taught obedience to authority; the King James Bible would correct that.
Given these complexities, Williams judged it impossible for any human to interpret all Scripture without error. Therefore he considered it "monstrous" for one person to impose any religious belief on another. He also realized that any government-sponsored prayer required a public official to pass judgment on something to do with God, a sacrilegious presumption. He also knew that when one mixes religion and politics, one gets politics. So to protect the purity of the church, he demanded — 150 years before Jefferson — a "wall of separation between the garden of the church and the wilderness of the world."
Massachusetts had no such wall, compelled religious conformity and banished Williams for opposing it. Seeking "soul liberty," he founded Providence Plantations and established an entirely secular government that granted absolute freedom of religion. The governing compact of every other colony in the Americas, whether English, French, Spanish or Portuguese, claimed the colony was being founded to advance Christianity. Providence's governing compact did not mention God. It did not even ask God's blessing.
Williams next linked religious and political freedom. It was then universally believed that governments derived their authority from God. Even Winthrop, after being elected governor in Massachusetts, told voters, "Though chosen by you, our authority comes from God."
Williams disputed this. Considering the state secular, he declared governments mere "agents" deriving their authority from citizens and having "no more power, nor for longer time, than the people … shall betrust them with." This statement sounds self-evident now. It was revolutionary then.
The U.S. Constitution, like Providence's compact, does not mention God. It does request a blessing, but not from God; it sought "the blessings of liberty," Williams' "soul liberty." As Justice Robert Jackson wrote, "This freedom was first in the Bill of Rights because it was first in the forefathers' minds; it was set forth in absolute terms, and its strength is its rigidity."
Eight years after the Constitution's adoption, the Senate confirmed this view in unanimously approving a treaty. It stated: "[T]he government of the United States is not in any sense founded on the Christian religion."
Yet the argument continues. Presidential candidates and evangelicals ignore American history and insist on injecting religion into politics. They proclaim their belief in freedom — even while they violate it.>>>
