First Barbary War: Battle of Derna

First Lieutenant Presley O'Bannon

US Marine Corps

The Battle of Derna took place during the First Barbary War.

William Eaton and First Lieutenant Presley O'Bannon captured Derna on April 27, 1805, and successfully defended it on May 13.

Armies & Commanders

United States

  • William Eaton
  • First Lieutenant Presley O'Bannon
  • 10 US Marines and soldiers
  • 200 Christian mercenaries
  • 200-300 Muslim mercenaries


  • Hassan Bey
  • Approx. 4,000 men

William Eaton

In 1804, during the fourth year of the First Barbary War, the former American consul to Tunis, William Eaton returned to the Mediterranean. Titled "Naval Agent to the Barbary States," Eaton had received support from the US government for a plan to overthrow the pasha of Tripoli, Yusuf Karamanli. After meeting with the commander of US naval forces in the area, Commodore Samuel Barron, Eaton traveled to Alexandria, Egypt with $20,000 to seek out Yusuf's brother Hamet. The former pasha of Tripoli, Hamet had been deposed in 1793 and then exiled by his brother in 1795.

A Small Army

After contacting Hamet, Eaton explained that he wished to raise a mercenary army to help the former pasha regain his throne. Eager to retake power, Hamet agreed and work began to build a small army. Eaton was aided in this process by First Lieutenant Presley O'Bannon and eight US Marines, as well as Midshipman Pascal Peck. Assembling a ragtag group of around 500 men, mostly Arab, Greek, and Levantine mercenaries, Eaton and O'Bannon set off across the desert to capture the Tripolitan port of Derna.

Setting Out

Departing Alexandria on March 8, 1805, the column moved along the coast pausing at El Alamein and Tobruk. Their march was supported from the sea by the warships USS Argus, USS Hornet, and USS Nautilus under the command of Master Commandant Isaac Hull. Shortly after the march began, Eaton, now referring to himself as General Eaton, was forced to deal with a growing rift between the Christian and Muslim elements in his army. This was made worse by the fact that his $20,000 had been used and money to fund the expedition was growing scarce.

Tension Among the Ranks

On at least two occasions, Eaton was forced to contend with near mutinies. The first involved his Arab cavalry and was put down at bayonet-point by O'Bannon's Marines. A second occurred when the column lost contact with Argus and food became scarce. Convincing his men to eat a pack camel, Eaton was able to stall until the ships reappeared. Pressing on through heat and sand storms, Eaton's force arrived near Derna on April 25 and was resupplied by Hull. After his demand for the city's surrender was refused, Eaton maneuvered for two days before initiating his attack.

Moving Forward

Dividing his force in two, he sent Hamet southwest to severe the road to Tripoli and then attack the western side of the city. Moving forward with the Marines and the other mercenaries, Eaton planned to assault the harbor fortress. Attacking on the afternoon of April 27, Eaton's force, supported by naval gunfire, met determined resistance as the city's commander, Hassan Bey, had reinforced the harbor defenses. This permitted Hamet to sweep into the western side of the city and capture the governor's palace.

Wounded, Yet Triumphant

Grabbing a musket, Eaton personally led his men forward and was wounded in the wrist as they drove the defenders back. By the end of the day, the city had been secured and O'Bannon hoisted the US flag over the harbor defenses. It was the first time the flag had flown over a foreign battlefield. In Tripoli, Yusuf had been aware of the approach of Eaton's column and had dispatched reinforcements to Derna. Arriving after Eaton had taken the city, they briefly laid siege before assaulting it on May 13. Though they pushed Eaton's men back, the attack was defeated by fire from the harbor batteries and Hull's ships.


The Battle of Derna cost Eaton a total of fourteen dead and several wounded. Of his force of Marines, two were killed and two wounded. O'Bannon and his Marines' role has been commemorated by the line "to the shores of Tripoli" in the Marine Corps Hymn as well as the adoption of the Mamaluke sword by the Corps. Following the battle, Eaton began planning a second march with the goal of taking Tripoli. Concerned about Eaton's success, Yusuf began suing for peace. Much to Eaton's displeasure, Consul Tobias Lear concluded a peace treaty with Yusuf on June 4, 1805, which ended the conflict. As a result, Hamet was sent back to Egypt, while Eaton and O'Bannon returned to the United States as heroes.


Smitha, Frank E. . First Barbary War Overview

Jewett, Thomas. Terrorism in Early America.

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Hickman, Kennedy. "First Barbary War: Battle of Derna." ThoughtCo, Aug. 26, 2020, Hickman, Kennedy. (2020, August 26). First Barbary War: Battle of Derna. Retrieved from Hickman, Kennedy. "First Barbary War: Battle of Derna." ThoughtCo. (accessed March 24, 2023).