According to Wikipedia, pastor Richard Allen started "the first independent black denomination in the United States" in 1816 and served as the African Methodist Episcopal Church's first bishop.
Allen grew up in Pennsylvania and Delaware as a slave and was know as "Negro Richard." Allen's master Stokeley Sturgis heard a sermon about slavery and was convicted. Sturgis then gave his slaves the opportunity to purchase their freedom. After Allen purchased his freedom, he changed his name to Richard Allen.
As a slave Allen attended Methodist church meetings and began to witness to other slaves. As a freeman, Allen preached at Philadelphia's St. George Methodist Episcopal Church. The church segregated blacks and whites which caused resentment and led to Allen starting the Free African Society.
Allen and his wife Sara assisted runaway slaves. The Early America Review reports that after efforts by African-Americans to resettle in Haiti failed, Allen wrote in Freedom's Journal, America's first black newspaper: "This land which we have watered with our tears and our blood is now our mother country."