Williams was born in Cowley, Middlesex, England, on 21 Dec. 1603. At age 12 he had a conversion experience of which his father disapproved. His father, James Williams (1562 – 1620), was a merchant tailor in Smithfield, England. His mother was Alice Pemberton (1564 – 1634).

As a teenager Williams apprenticed with Sir Edward Coke (1552 – 1634), the famous jurist, and under Coke's patronage, Williams was educated at Charterhouse and also at Pembroke College, Cambridge (B.A., 1627). He seemed to have had a gift for languages, and early acquired familiarity with Latin, Hebrew, Greek, Dutch, and French. Years later he gave John Milton lessons in Dutch in exchange for refresher lessons in Hebrew.

Although he took Holy Orders in the Church of England, he had become a Puritan at Cambridge, forfeiting any chance at a place of preferment in the Anglican church. After graduating from Cambridge, Williams became the chaplain to a Puritan lord, Sir William Macham. He married Mary Barnard (1609 – 76) on December 15, 1629 at the Church of High Laver, Essex, England. They had six children, all born in America. Their children were Mary, Freeborn, Providence, Mercy, Daniel and Joseph.

Williams was privy to the plans of the Puritan leaders to migrate to the New World, and while he did not join the first wave in the summer of 1630, before the end of the year, he decided he could not remain in England under Archbishop William Laud's rigorous (and High church) administration. He regarded the Church of England to be corrupt and false, and by the time he and his wife boarded the Lyon in early December, he had arrived at the Separatist position.

When Roger and Mary Williams arrived at Boston on February 5, 1631, he was welcomed and almost immediately invited to become the Teacher (assistant minister) in the Boston church to officiate while Rev. John Wilson returned to England to fetch his wife. He shocked them by declining the position, saying that he found that it was "an unseparated church." In addition he asserted that the civil magistrates may not punish any sort of "breach of the first table [of the Ten Commandments]," such as idolatry, Sabbath breaking, false worship, and blasphemy, and that every individual should be free to follow his own convictions in religious matters. Right from the beginning, he sounded three principles which were central to his subsequent career: Separatism, freedom of religion, and separation of church and state.

As a Separatist he had concluded that the Church of England was irredeemably corrupt and that one must completely separate from it to establish a new church for the true and pure worship of God. His search for the true church eventually carried him out of Congregationalism, the Baptists, and any visible church. From 1639 forward, he waited for Christ to send a new apostle to reestablish the church, and he saw himself as a "witness" to Christianity until that time came. He believed that soul liberty freedom of conscience, was a gift from God, and that everyone had the natural right to freedom of religion. Religious freedom demanded that church and state be separated. Williams was the first to use the phrase "wall of separation" to describe the relationship of the church and state. He called for a high wall of separation between the "Garden of Christ" and the "Wilderness of the World." This idea might have been one of the foundations of the religion clauses in the U.S. Constitution, (although the language used by the founders is quite different) and First Amendment to the United States Constitution. Years later, in 1802 Thomas Jefferson, writing of the "wall of separation" echoed Roger Williams in a letter to the Danbury Baptist Association.

The Salem church was much more inclined to Separatism, so they invited Williams to become their Teacher. When the leaders in Boston learned of this, they vigorously protested, and the offer was withdrawn. By the end of the summer of 1631, Williams had moved to Plymouth colony where he was welcomed, and informally assisted the minister there. He regularly preached and according to Governor Bradford, "his teachings were well approved."

After a time, Williams felt disappointed that the Plymouth church was not sufficiently separated from the Church of England, and his study of the Native Americans had caused him to doubt the validity of the colonial charters. Governor Bradford later wrote that Williams fell "into some strange opinions which caused some controversy between the church and him." In December 1632 he wrote a lengthy tract which openly condemned the King's charters and questioned the right of Plymouth (or Massachusetts) to the land without first buying it from the Indians. He charged that King James had uttered a "solemn lie" when he asserted that he was the first Christian monarch to have discovered the land. Subsequently, he moved back to Salem by the fall of 1633 and was welcomed by Rev. Samuel Skelton as an unofficial assistant in the church.

The Massachusetts authorities were not pleased to see Williams return, and when they learned of his tract attacking the King and the charters, he was summoned in December 1633 to appear before the General Court in Boston. The issue was smoothed out, and the tract disappeared forever, probably burned. In August, 1634 (Rev. Skelton having died), Williams became acting pastor of the Salem church and continued to be embroiled in controversies. He had promised earlier not to raise the issue of the charter again, but he did. Again, in March 1635 was ordered to appear before the General Court to explain himself. In April he so vigorously opposed the new oath of allegiance to the colonial government that it became impossible to enforce it. He was summoned again before the Court in July to answer for "erroneous" and "dangerous opinions," and the Court declared that he should be removed from his church position. This latest controversy welled up at just the moment that the Town of Salem had petitioned the General Court to annex some land on Marblehead Neck. The Court would not consider the request until the Salem church removed Williams. The Salem church felt that this order violated the independence of the church, and a letter of protest was sent to the other churches. However, the letter was not read, and the General Court refused to seat the delegates from Salem at the next session. Support for Williams began to wane under this pressure, and when Williams demanded that the Salem church separate itself from other churches, his support crumbled entirely. He withdrew and met in his home with a few of his most devoted followers.

Finally, in October 1635 he was tried by the General Court and convicted of sedition and heresy. The Court declared that he was spreading "diverse, new, and dangerous opinions." He was ordered to be banished. (This order was not repealed until 1936 when Bill 488 was passed by the Massachusetts House.) The execution of the order was delayed because Williams was ill and winter was approaching, and he was allowed to stay temporarily provided he ceased his agitation. He did not cease, so in January 1636 the sheriff came to pick him up only to discover that Williams had slipped away three days before. He walked through the deep snow of a hard winter the 105 miles from Salem to the head of Narragansett Bay. There he was rescued by his friends, the Wampanoags, and taken to the winter camp of their chief sachem, Massasoit.

In the spring of 1636 Williams and a number of his followers from Salem began a settlement on land that Williams had bought from Massasoit, only to be told by Plymouth that he was still within their land grant. They warned that they might be forced to extradite him to Massachusetts and invited him to cross the Seekonk River to territory beyond any charter. The outcasts rowed over to Narragansett territory, and having secured land from Canonicus and Miantonomi, chief sachems of the Narragansetts, Williams established a settlement with twelve "loving friends." He called it "Providence" because he felt that God's Providence had brought him there. (He would later name his third child, the first born in his new settlement, "Providence" as well.) He said that his settlement was to be a haven for those "distressed of conscience," and it soon attracted quite a collection of dissenters and otherwise minded individuals.

From the beginning, the settlement was governed by a majority vote of the heads of households, but "only in civil things," and newcomers could be admitted to full citizenship by a majority vote. In August of 1637 they drew up a town agreement, which again restricted the government to "civil things." In 1640, another agreement was signed by thirty - nine "freemen," (men who had full citizenship and voting rights) which declared their determination "still to hold forth liberty of conscience." Thus, Williams had founded the first place in modern history where citizenship and religion were separated, a place where there was religious liberty and separation of church and state.

In November 1637, the General Court of Massachusetts disarmed, disenfranchised, and forced into exile the Antinomians, the followers of Anne Hutchinson. One of them, John Clarke, learned from Williams that Aquidneck Island might be purchased from the Narragansetts. Williams facilitated the purchase by William Coddington and others, and in the spring of 1638 the Antinomians began settling at a place called Pocasset, which is now the town of Portsmouth, Rhode Island. Some of the Antinomians, especially those described by Governor John Winthrop as "Anabaptists," settled in Providence.

In the meantime, the Pequot War had broken out, and it was a great irony that Massachusetts Bay was forced to ask for Roger Williams' help. He not only became the Bay colony's eyes and ears, he used his relationship with the Narragansetts to dissuade them from joining with the Pequots. Instead, the Narragansetts allied themselves with the English and helped to crush the Pequots in 1637 - 1638. When the war was over, the Narragansetts were clearly the most powerful Indian nation in southern New England, and quite soon the other New England colonies began to fear and mistrust the Narragansetts. They came to regard Roger Williams' colony and the Narragansetts as a common enemy. In the next three decades Massachusetts, Connecticut, and Plymouth exerted pressure to destroy both Rhode Island and the Narragansetts.

In 1643, the neighboring colonies formed a military alliance called the United Colonies and pointedly excluded the towns around Narragansett Bay. The object was to extend their power over the heretic settlements and put an end to the infection. In response Williams was sent to England by his fellow citizens to secure a charter for the colony. The English Civil War was in full swing in England when Williams arrived. The Puritans were then in power in London, and through the offices of Sir Henry Vane a charter was obtained despite strenuous opposition from agents from Massachusetts. Historians agree that the key that unlocked the door for Williams was his first published book, A Key Into the Language of America (1643). Printed by John Milton's publisher the book was an instant "best - seller," and gave Williams a large and favorable reputation. This little book was the first dictionary of any Indian tongue in the English language and fed the great hunger of the English about the Native Americans. Having secured his precious charter for "Providence Plantations" from Parliament, in July 1644 Williams then published his most famous book, The Bloody Tenent of Persecution for Cause of Conscience. This produced a great uproar, and Parliament responded in August by ordering the book to be burned by the public hangman. By then, Williams was already on his way home to Providence Plantations. Also, by then, the settlers on Aquidneck Island had renamed their island "Rhode Island."

Because of opposition from William Coddington on "Rhode Island," it took Williams until 1647 to get the four towns around Narragansett Bay to unite under a single government, and liberty of conscience was again proclaimed. The colony became a safe haven for people who were persecuted for their beliefs including Baptists, Quakers, and Jews. Still, the divisions between the towns and powerful personalities did not bode well for the colony. Coddington, who never liked Williams nor liked being subordinated to the new charter government, sailed to England and returned in 1651 with his own patent making him "Governor for Life" over "Rhode Island" [Aquidneck] and Conanicut. As a result, Providence and Warwick dispatched Roger Williams and Coddington's opponents on "Rhode Island" sent John Clarke to England to get Coddington's commission canceled. To pay for the trip, Williams sold his trading post at Cocumscussec, near present day Wickford, Rhode Island. This trading post was his main source of income. Williams and Clarke were successful in getting Coddington's patent rescinded, but Clarke remained in England until 1664 to secure a new charter for the colony. Williams returned to America in 1654 and was immediately elected the President of the colony. He would subsequently serve in many offices in the town and colonial governments, and in his 70s he was elected captain of the militia in Providence during King Philip's War in 1676.

One notable effort by "Providence Plantations" (Providence and Warwick) during the time when Coddington had separated "Rhode Island" (Newport and Portsmouth) from the mainland came on May 18, 1652, when they passed a law which attempted to prevent slavery from taking root in the colony. In 1641 Massachusetts Bay had passed the first laws to make slavery legal in the English colonies, and these laws spread to Plymouth and Connecticut with the creation of the United Colonies in 1643. Roger Williams and Samuel Gorton both opposed slavery, and the law passed in 1652 was the attempt to stop slavery from coming to Rhode Island. Unfortunately, when the parts of the colony were reunited, the Aquidneck towns refused to accept the law and it became a dead letter. The economic and political center of Rhode Island and Providence Plantations was Newport for the next 100 years, and they disregarded the anti - slavery law. Indeed, Newport entered the African slave trade in 1700 and became the leading American slave traders from then until the American Revolution.

By 1638, Williams' ideas had ripened to the point that he accepted the idea of believer's baptism, or credobaptism. Williams had been holding services in his home for some time for his neighbors, many of whom had followed him from Salem. To that point they had been like the Separatists of Plymouth, still believing in infant baptism. Williams came to accept the ideas of English anti - pedobaptists.

John Smyth, Thomas Helwys, and John Murton were co-founders of the Baptist movement in England, and produced a rich literature advocating liberty of conscience. Williams certainly had read some of their writings because he commented on them in his Bloudy Tenent. While Smyth, Helwys and Murton were General Baptists, a Calvinistic Baptist variety grew out of some Separatists around 1630. Williams became a Calvinist or Particular Baptist (Reformed Baptist).

However, Williams had not adopted anti - pedobaptist views before his banishment from Massachusetts, for anti - pedobaptism was not a charge leveled at him by his opponents. Winthrop attributed Williams's "Anabaptist" views to the influence of Katherine Scott, a sister of Anne Hutchinson, who may have impressed upon Williams the importance of believers' baptism. Historians tend to think that Williams arrived there from his own study.

Williams had himself baptized by Ezekiel Holliman in late 1638. Thus was constituted a church which still survives as the First Baptist Church in America. A few years later, John Clarke, Williams’ compatriot in the cause of religious freedom in the New World, established a Baptist church in Newport, Rhode Island. In 1847 the Newport church suddenly maintained that it was the first Baptist church in America, but virtually all historians have dismissed this claim. If nothing else, Roger Williams had gathered and resigned from the Providence church before the town of Newport was even founded. Still, both Roger Williams and John Clarke are variously credited as being the founder of the Baptist faith in America.

It should be noted that Roger Williams was a Baptist only briefly. He remained with the little church in Providence only a few months. He became convinced that the ordinances, having been lost in the Apostasy [when Christianity became the official religion of the Roman Empire], could not be validly restored without a special divine commission. He declared: "There is no regularly constituted church of Christ on earth, nor any person qualified to administer any church ordinances; nor can there be until new apostles are sent by the Great Head of the Church for whose coming I am seeking."

He never again affiliated himself with any church, but remained deeply religious and active in preaching and praying. He looked forward to the time when Christ would send a new apostle to restore the church, but in the meantime, he would be a "witness" to Christianity. He always remained interested in the Baptists, being in agreement with them in their rejection of infant baptism as in most other matters. He has been mistakenly called a "Seeker", both in his own time by his enemies and by his admirers in the last century. Some of his enemies in England called him a “Seeker” in an attempt to smear him by associating him with a heretical movement that accepted Socianism and universal salvation. Both of these ideas were anathema to Williams. He was like a Seeker only in his rejection of any visible church as being a true church. A twentieth century biographer revived the Seeker label, but regarded it as a positive thing, and it caught on.

Williams had read their writings, and his own experience of persecution by Archbishop Laud and the Anglican establishment and the bloody wars of religion that raged in Europe at that very time convinced him that a state church had no basis in Scripture. Clearly he had arrived at this conclusion before he landed in Boston in 1631 because he criticized the Massachusetts Bay system immediately for mixing church and state. He declared that the state could legitimately concern itself only with matters of civil order, but not religious belief. The state had no business in trying to enforce the “first Table” of the Ten Commandments, those first commandments that dealt with the relationship between God and persons. The state must confine itself to the commandments that dealt with the relations between people: murder, theft, adultery, lying, honoring parents, and so forth. He regarded any effort by the state to dictate religion or promote any particular religious idea or practice to be “forced worship.” And he colorfully declared that “forced worship stinks in the nostrils of God.” He would write that he saw no warrant in the New Testament to use the sword to promote religious belief. Indeed, he said that Constantine had been a worse enemy to true Christianity than Nero because Constantine’s support had corrupted Christianity and led to the death of the Christian church. In the strongest language he described the attempt to compel belief to be rape of the soul, and he spoke of the “oceans of blood” shed as a result of trying to command conformity. He believed that the moral principles found in the Scriptures ought to inform the civil magistrates, but he observed that well ordered, just, and civil governments existed where Christianity was not present. All governments were required to maintain civil order and justice, but none had a warrant to promote any religion.

Most of Williams’s contemporaries and critics regarded his ideas as a prescription for chaos and anarchy. The vast majority believed that each nation must have its national church and that dissenters had to be compelled to conform. The establishment of Rhode Island was so threatening to its neighbors that they tried for the next hundred years to extinguish the “lively experiment” in religious freedom that had begun in 1636.

Williams died on April 1, 1683 and was buried on his own property. Fifty years later, his house had collapsed into the cellar and the location of his grave had been forgotten. In 1860, Zachariah Allen sought to locate his remains, but found nothing. In the grave that Allen thought was that of Williams, he found the apple tree root, but little else. Some dirt from the hole was placed in the Randall family mausoleum in the North Burial Ground. In anticipation of the 300th anniversary of the founding of Providence, the dirt was retrieved from the mausoleum and placed in an urn and kept at the Rhode Island Historical Society until a proper monument was erected at Prospect Terrace Park in Providence. The actual deposit of the “dust from the grave of Roger Williams” did not occur until 1939 when the WPA finished the monument. The apple tree root is now regarded as a curio and kept by the Rhode Island Historical Society at the John Brown House Museum.

Williams's career as an author began with A Key into the Language of America (London, 1643), written during his first voyage to England. His next publication was Mr. Cotton's Letter lately Printed, Examined and Answered (London, 1644; reprinted, with Cotton's letter, which it answered, in Publications of the Narragansett Club, vol. ii.).

The Bloody Tenent of Persecution, for Cause of Conscience soon followed (London, 1644). This is his most famous work, and was the ablest statement and defense of the principle of absolute liberty of conscience that had appeared in any language. It is in the form of a dialogue between Truth and Peace, and well illustrates the vigor of his style.

During the same year an anonymous pamphlet appeared in London which now is ascribed to Williams, entitled: Queries of Highest Consideration Proposed to Mr. Tho. Goodwin, Mr. Phillip Nye, Mr. Wil. Bridges, Mr. Jer. Burroughs, Mr. Sidr. Simpson, all Independents, etc. These Independents were members of the Westminster Assembly and their Apologetical Narration, sought to find a way between extreme Separatism and Presbyterianism, and their prescription was the acceptance of the state church model of Massachusetts Bay. Williams attacked their arguments for the very same reasons that he found that Massachusetts Bay violated liberty of conscience.

In 1652, during his second visit to England, Williams published The Bloody Tenent yet more Bloody: by Mr. Cotton's Endeavor to wash it white in the Blood of the Lamb; of whose precious Blood, spilt in the Bloud of his Servants; and of the Blood of Millions spilt in former and later Wars for Conscience sake, that most Bloody Tenent of Persecution for cause of Conscience, upon, a second Tryal is found more apparently and more notoriously guilty, etc. (London, 1652). This work reiterated and amplified the arguments in Bloody Tenent; but it has the advantage of being written in answer to Cotton's elaborate defense of New England persecution, A Reply to Mr. Williams his Examination (Publications of the Narragansett Club, vol. ii.).

Other works by Williams are:

• The Hireling Ministry None of Christ's (London, 1652)
• Experiments of Spiritual Life and Health, and their Preservatives (London, 1652; reprinted Providence, 1863)
• George Fox Digged out of his Burrowes (Boston, 1676).

A volume of his letters is included in the Narragansett Club edition of Williams's Works (7 vols., Providence, 1866 – 74), and a volume was edited by J.R. Bartlett (1882).

• The Correspondence of Roger Williams, 2 vols., Rhode Island Historical Society, 1988, edited by Glenn W. LaFantasie.

Williams intended to become a missionary to the Native Americans and set out to learn their language. He studied their language, customs, religion, family life and other aspects of their world. As a result he came to see their point of view about colonization and developed a deep appreciation of them as people. He wrote his A Key into the Language of America (1643) as a kind of phrase book coupled with observations about life and culture as an aid in communication with the Indians. In it he talked about everything from salutations in the first chapter to death and burial in chapter 32. The book also sought to instruct the English, who thought of themselves as vastly superior to the Native Americans, that they were mistaken. He repeatedly made the point that the Indians were just as good as the English, even superior in some respects.

"Boast not proud English, of thy birth & blood;
Thy brother Indian is by birth as Good.
Of one blood God made Him, and Thee and All,
As wise, as fair, as strong, as personal."

Having learned their language and customs, Williams gave up the idea of being a missionary and never baptized a single Indian. He was severely criticized by the Puritans for failing to Christianize them, but Williams had arrived at the place in his own thinking that no valid church existed. He said he could have baptized the whole country, but it would have been hypocritical and false. He formed firm friendships and developed deep trust among the Native Americans, especially the Narragansetts. He was able to keep the peace between the Indians and English in Rhode Island for nearly forty years because of his constant mediation and negotiation. He twice surrendered himself as a hostage to the Indians to guarantee the safe return of a great sachem from a summons to a court: Pessicus in 1645 and Metacomet (King Philip) in 1671. He more than any other Englishman was trusted by the Native Americans and proved to be trustworthy. In the end King Philip’s War (1675 – 1676) was one of the bitterest events in his life as his efforts ended with the burning of Providence in March 1676, including his own house.

Moore (1963) traces the 'negative' approach of the orthodox Puritan writers (Bradford, Winthrop, Morton, Cotton Mather, Hutchinson, Winsor and Dexter), the 'romantic' approach (George Bancroft, Vernon Parrington, Ernst and Brockunier) and the 'realistic' approach (Backus, H. Richard Niebuhr, Roland Bainton and Hudson), and regards the work of Mauro Calamandrei, who was followed by Perry Miller and Ola Winslow, as crucial. The realistic writers created a synthesis of the earlier interpretations.

Williams has been considered an American hero ever since the Puritans of his own day stopped dominating historical interpretations. His defense of Native Americans, accusations that Puritans had reproduced the "evils" of the Anglican Church, and denial that the king had authority to grant charters for colonies put him at the center of nearly every political debate during his life. By the time of American independence, however, he was considered a defender of religious freedom and has continued to be praised by generations of historians who have often altered their interpretation of his period as a whole. Historians have been able to appropriate Williams because he was unusual, prolific and vague.

• Roger Williams Cenotaph in Green - Wood Cemetery, Brooklyn, Kings County, N.Y.
• Roger Williams National Memorial, established in 1965, is a park in downtown Providence.
• Roger Williams Park, Providence, Rhode Island, and the Roger Williams Park Zoo within it are named in his honor.
• Roger Williams University, in Bristol, Rhode Island, is named in his honor.
• Roger Williams Dining Hall, at the University of Rhode Island, was named after the co-founder of Rhode Island. Today, it is fondly referred to as "Rojo's."
• The Green Lake Conference Center (American Baptists), founded in 1943, in Green Lake, Wisconsin, has dedicated its main lodge as the, "Roger Williams Inn."
• Roger Williams was selected in 1872 to represent Rhode Island in the National Statuary Hall Collection in the United States Capitol.
• Roger Williams is depicted, with other prominent reformers, on the International Monument to the Reformation in Geneva, Switzerland.
• An album The Bloudy Tenent Truth Peace by Slim Cessna's Auto Club makes an allusion to Roger William's 1644 book, The Bloudy Tenent of Persecution for Cause of Conscience and features He, Roger Williams. A song dedicated to him as being the founder of the first Baptist church in America.
• Williams is honored with Anne Hutchinson with a feast day on the liturgical of the Episcopal Church in the United States of America on February 5.