Penn's "holy experiment" was successful at many levels. Among the youngest of the American colonies, Pennsylvania quickly prospered attracting immigrants not only from other colonies and the British Isles, but from the European continent as well. In the Old World, many were persecuted for their faith and sought the freedom to live by their beliefs in a new land of opportunity.
Penn's capital city of Philadelphia flourished to become the largest metropolitan center in North America at the time of the American Revolution. Its religious communities included: Quakers, Anglicans, Presbyterians, Baptists, Lutherans, Brethren, Mennonites, Catholics, Jews, and others, an unparalleled religious pluralism in America at the time. Pennsylvania's ethnic diversity was equally impressive and inclusive, and yet slavery remained a blind spot of Penn's social vision. The colony's Charter of Privileges or 1701 Frame of Government, codified freedom of conscience and religious liberty. At the time, Pennsylvania was one of the most free and democratic governments in the world.
Later America founders like Thomas Jefferson and James Madison were inspired by William Penn and his laws, noting his philanthropy and contributions to civil and religious liberty. His legal protections for religious freedom chartered a rare pluralism that fostered a civic order of tolerance where a diversity of peoples and faith traditions could live together with their deepest differences. Penn's vision of brotherly love continues to inspire citizens to strive for peace and harmony in their common life, even as America's pluralism expands beyond anything Penn could have imagined in his own day. His vision of brotherly love and religious freedom remains relevant, and perhaps even needful, in America's ongoing experiment of liberty and justice for all.