William Penn (1644-1718), born in London, was the eldest son of Sir William Penn, an English Admiral, and Margaret Jasper. He was educated at The Free School, Chigwell and Christ Church, Oxford. Judged for his nonconformity, in 1661, his father sent him to Europe, from which he returned in 1664 a “modish person.” He entered Lincoln's Inn to study law in 1665, but soon after went to Ireland where he was convinced by Thomas Loe to Quakerism, and was shortly arrested at a Quaker Meeting in Cork. By 1668, he published The Sandy Foundation Shaken for which he was again arrested. He continued to publish works on Quaker doctrinal issues. In 1671, he travelled to Holland and Germany encouraging Quaker communities, preaching and writing against religious persecution. He used his family influence to help Quaker friends, including George Fox and Isaac Pennington. Penn married Gulielma Springett in 1672 and Hannah Callowhill in 1696.

In 1676, Penn became a trustee of the Quaker colony of West New Jersey and in 1681, in exchange for a large debt owed by Charles II to his father, he was granted the province of Pennsylvania. William Penn's aim was to create a colony with the greatest possible civil and religious liberty for all Christians. In 1682, Penn sailed to America, but returned to England in 1684. He spent most of the 1690s writing, preaching and trying to resolve the politicial, military, imperial and constitutional problems of his colony. Almost all his political writings adressed issues of liberty and conscience. The exception was his utopian idea for securing permanent peace in Europe (Essay Towards the Present and Future Peace of Europe). In 1699, he returned to America and then again to England in 1701. In 1707, he spent nine months in debtors' prison, and on his release, he mortgaged his American properties and tried to sell them back to the Crown. He suffered a paralytic stroke in 1712 from which he never recovered

Penn's philosophy was a combination of religious idealism and political practicalites. His arguments for toleration are grounded in a secular and expansive version of interest theory. He believed that oppressed subjects were a threat to peace, stability and prosperity and that true religion was a matter for individual conscience, not legislation. There was never a question of tolerating non-Christians or atheists. He never advocated a separation of Church and State, nor for the secularization of civil affairs.

Biographical information from article by Martyn P. Thompson in Dictionary of Seventeenth Century British Philosophers. Sterling, Virginia: Thoemmes Press, 2000