| Chick here for other symbols. | Click here for monuments related to slavery. 1731-1809 - Benjamin Banneker - African-American surveyor & mathematician. c1735-1807 - Prince Hall - Abolitionist. Founder of "Black Freemasonry." c1745-1797 - Olaudah Equiano - Slave who purchased his own freedom. Became author, merchant & explorer. Influenced enactment of