William PennPenn, William (1644–1718) an English leader of the Quakers (=a Christian religious group), who was put in prison for having unacceptable religious beliefs. After he was let out of prison, he was given some land in North America, and he established a colony there as a place of religious freedom for Quakers and others to go and live in. He called the colony Pennsylvania, and planned and built the city of Philadelphia in 1682.