Battle of Derna

William Eaton leading the attack on Derne with the Marines, soldiers and mercenaries under his command

Date	April 27 – May 13, 1805
Location	Derne, Cyrenaica
Result	Decisive American victory

Belligerents

United States

Eyalet of Tripolitania

Commanders and leaders

William Eaton
Presley O’Bannon
Oliver Hazard Perry
Hamet Bey

Hassan Bey

Strength

8 U.S. Marines
400–500 mercenaries
Unknown artillery
1 sloop-of-war
1 brig
1 schooner

4,000 infantry, cavalry
Unknown artillery

Casualties and losses

United States:
2 killed
3 wounded
Christian mercenaries:
9 killed and wounded
Muslim mercenaries:
Unknown

Unknown

The Battle of Derna was the decisive victory of a mercenary army recruited and led by U.S. Marines under the command of U.S. Army Lieutenant William Eaton and U.S. Marine Corps First Lieutenant Presley Neville O’Bannon. The battle involved a forced 600-mile march through the desert to the city of Derna, Libya, which was defended by a much larger force.

In 1804 the former Consul to Tunis, William Eaton returned to the Mediterranean with the title of Naval Agent to the Barbary States. Eaton had been granted permission from the United States government to back the claim of Hamet Karamanli. Hamet Karamanli was the rightful heir to the throne of Tripoli and had been deposed by his brother Yussif Karamanli. Upon his return to the area, Eaton sought out Hamet Karamanli who was in exile in Egypt. Upon locating him, Eaton made a proposal to reinstate him on the throne. The exile agreed to Eaton's plan.Commodore Samuel Barron, the new naval commander in the Mediterranean, provided Eaton with naval support from USS Nautilus, USS Hornet and USS Argus. The three vessels were to provide offshore bombardment support.Nautilus was commanded by Oliver Hazard Perry, Hornet by Samuel Evans, and Argus by Isaac Hull. A small detachment of U.S. Marines was given to Eaton commanded by First Lieutenant Presley O'Bannon. Eaton and Hull based their operations at Alexandria, Egypt. With the help of Hamet Karamanli, they recruited about 400 Arab and Greek mercenaries. Eaton became general and commander-in-chief of the combined force.

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