APRIL 27, 1805: William Eaton and a detachment of ten Marines lead by Lieutenant Presley O’Bannon assault the Tripolitan port city of Derne in an operation against the predatory Barbary States of North Africa. Eaton and the Marines had led a mercenary army of some 400 men on a six-week, 600-mile journey across the desert to install the city’s rightful heir, who promised to end the state’s demands for tribute. Aided by gunfire from three U.S. Navy ships, the Marines captured the city, a feat memorialized in the Marine Corps hymn “to the shores of Tripoli.”