In 1865, Rev. Henry Highland Garnet, a former slave, became the first black to speak in the Capitol Building in Washington, DC. His sermon was delivered on Sunday, February 12, 1865 within days of Congress's adoption of the 13th Amendment banning slavery. A number of Republican leaders thought the occasion merited a public religious service to commemorate the event. They extended the invitation to Rev. Garnet. His sermon titled, “Let the Monster Perish,” appears in the link.