Born into a slaveholding Quaker family in Virginia, Warner Mifflin later came to Delaware as a young man and became an abolitionist. An elder of the Religious Society of Friends, he traveled extensively to persuade others to free their slaves and manumitted his own in 1774-75. In 1788, he was one of the founders of Delaware's first abolition society. During the American Revolution, he advocated peace and traveled with a committee of Quakers to meet both American General George Washington and British General William Howe to present a testimony against war during the Battle of Germantown. He was interred here on October 16, 1798.