In 1733 a tiny chapel was established by Jesuits for Philadelphia's 11 Catholic families. It was one of the first places in the English-speaking colonies where Catholic mass could be legally celebrated, a right granted under William Penn's 1701 Charter of Privileges, which guaranteed religious freedom. But freedom didn't come easy; on one occasion Quakers had to patrol St. Joseph's to prevent a Protestant mob from disrupting the service. The present church, built in 1839, is the third on this site. The late-19th-century stained-glass windows are notable.