April 27, 1805 — The Battle of Derna commences

The first extra-territorial land battle fought by the armed forces of young United States of America. It is the source of the Marine Corps Hymn (“To the Shores of Tripoli”), because the American forces – which consisted mostly of a few hundred mercenaries, backed by three ships – were led by 54 marines. It was the decisive engagement of the First Barbary War (fought between the United States and Sweden on one side and the so-called Barbary States – the Eyalet of Tripolitania and Morocco – on the other).

The battle itself took place after the mercenary forces, led by 8 US marines, attacked the fort at the city of Derna, taking it after heavy fighting against a greatly numerically superior enemy. The surrender of the Barbary forces came a month later, and the US set an early precedent for its poor treatment of its veterans by stiffing the mercenaries on part of their pay.