The Battle of Derna at Derne was the decisive victory in April–May 1805 of a mercenary army recruited and led by United States Marines under the command of U.S. Army Lieutenant William Eaton, (1764-1811), diplomatic Consul to Tripoli and U.S. Marine Corps First Lieutenant Presley Neville O’Bannon (1776-1850). The battle involved a forced 500-mile march through the North African desert from Alexandria, Egypt to the eastern port city of Derna, Libya, which was defended by a much larger force.
In 1804, the former Consul to Tunis, William Eaton (1764-1811) returned to the Mediterranean Sea with the title of Naval Agent to the Barbary States. Eaton had been granted permission from the United States government and third President Thomas Jefferson (1743-1826, served 1801-1809), 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 Yusuf Karamanli. Yusuf had assassinated his older brother by shooting him in front of his mother. Yusuf was out of the country at the time and decided to remain away, in exile. 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, (1765-1810), the new naval commander in the Mediterranean Sea, provided Eaton with naval support from several small warships of the U.S. Navy's Mediterranean squadron - USS Nautilus, commanded by Oliver Hazard Perry (1785-1819), USS Hornet, under Samuel Evans (c.1785-1824), and USS Argus, captained by Isaac Hull (1773-1843). The three vessels were to provide offshore bombardment support. A small detachment of U.S. Marines was given to Consul Eaton commanded by First Lieutenant Presley Neville O'Bannon, USMC, (1776-1850). Eaton and O'Bannon based their operations at Alexandria, Egypt. With the help of Hamet Karamanli, they recruited about 400 Arab, Turkish and Greek mercenaries. Eaton became self-appointed general and commander-in-chief of the combined multi-national force.
On March 6, 1805, Lieutenant Eaton (having grandly designated himself as "General" and commander in chief) began to lead his forces on a 500 miles (800 km) trek westward across the Libyan North African desert from Egypt. Their objective was the port city of Derne, capital of the Ottoman Empire province of Cyrenaica (in eastern modern Libya). The mercenary forces were promised supplies and money when they reached the city. During the 50-day trek, Eaton became worried over the strained relationship between the Greek Orthodox/Christian Greeks and the roughly 200 to 300 Muslim Arab and Turkish mercenaries. The expeditions supplies were dwindling with Eaton reporting in 1805 that, "Our only provisions [are] a handful of rice and two biscuits a day." At one point, some of the Arabs in the expedition made a desperate attempt to raid the supply wagon, but were beaten back by the Marines and a few Greek artilleryman, who used the expeditions lone cannon. Mutiny continuously threatened the success of the expedition on several occasions. Between March 10 and March 18, several Arab camel drivers mutinied before reaching the sanctuary of the Massouah Castle. From March 22 to March 30, several Arab mercenaries under the command of Sheik el Tahib staged mutinies. By April 8, when he crossed the border into Libya / Tripoli, Eaton had quelled the Arab mutinies. In late April, his army finally reached the port city of Bomba, on the Gulf of Bomba, some miles up the coast from Derne, where U.S. Navy warships Argus, Nautilus and Hornet with Commodore Barron and Captain Hull were waiting for him. Eaton received fresh supplies and the money to pay his mercenaries.
On the morning of April 26, Eaton sent a letter to Mustafa Bey, the governor of Derne, asking for safe passage through the city and additional supplies, though Eaton realized the governor probably would not agree. Mustafa reportedly wrote back, "My head or yours!". On the morning of April 27, Eaton observed a fort in Derne with eight guns. He believed the majority of the population would prefer to be ruled by Hamet. The brig USS Argus sent a cannon ashore to use in the attack. Captain Hull's ships then opened fire and bombarded Derne's batteries for an hour. Meanwhile, Eaton divided his army into two separate attacking parties. Hamet was to lead the Arab mercenaries southwest to cut the road to Tripoli, then attack the city's left flank and storm the weakly defended governor's palace. Eaton with the rest of the mercenaries and the squad of Marines would attack the harbor fortress. Hull and the ships would fire on the heavily defended port batteries. The attack began at 2:45 p.m., with Lt. O'Bannon and his Marines leading the advance. O'Bannon led his Marines and 50 Greek gunners with the field piece from the Argus, though the gun's effectiveness was lessened after the firing crew carelessly left the ramrod in the tube and fired it down range. The harbor defenses had been reinforced, and the attackers were temporarily halted. But this had weakened the defenses elsewhere and allowed the Arab mercenaries to ride unopposed into the western section of the city.
Eaton's mercenary army was hesitant under the enemy's musket fire, and he realized a charge was the only way to regain the initiative. Leading the charge, he was seriously wounded in the wrist by a musketball. On the Argus, Captain Hull saw the Americans and mercenaries were "gaining ground very fast though a heavy fire of Musquetry [sic] was constantly kept upon them." The ships ceased fire to allow the charge to continue. Eaton would report that O'Bannon with his Marines and Greeks "pass'd through a shower of Musketry from the Walls of houses, took possession of the Battery". The defenders fled in haste, leaving their cannons loaded and ready to fire. O'Bannon raised the American flag (the unique 15 stars - 15 stripes emblem used 1795-1818, later made famous in the War of 1812 as the "Star-Spangled Banner" over the battery, and Eaton turned the captured guns on the city. Hamet's force had seized the governor's palace and secured the western part of the city. Many of the defenders of the harbor fortress fled through the town and ran into Hamet's force. By 4:00 p.m. the entire city had fallen, and for the first time in history, an American flag flew over fortifications on the opposite side of the Atlantic Ocean. According to Tucker, casualties during the fighting for the Americans were two killed and three wounded, while those among the Christian / Greek mercenaries were nine killed or wounded. Muslim Turkish / Arab mercenary casualties are unknown, as are those of the defenders. Yusuf in Tripoli to the west was aware of the attack on Derne and had sent reinforcements to the city. By the time this force arrived, however, the city had fallen. His men dug in and prepared to recapture the city. Eaton fortified his new position, while Hamet took up residence in the governor's palace and had his Arabs patrolling the outer areas of the city. Yusuf's men dug in south of the city and waited. On May 13, they attacked the city and drove Hamet's Arabs back, almost recapturing the governor's palace. USS Argus and Eaton's captured batteries pounded the attackers, who finally fled under heavy fire. Nightfall found both sides back in their original positions. Skirmishes and several other minor attempts were made on the city in the following weeks, but the city remained in American control. From Derne, Eaton now planned to march across the desert and attack Tripoli from the land. During his march he was informed of the treaty signed on June 10, 1805, between American emissary Tobias Lear (1762-1816) from the U.S. Department of State and Yusuf Karamanli. In the middle of his trek Eaton was ordered to return to Egypt with Hamet.
The Battle of Derne was the first land battle of the United States on foreign soil after the American Revolutionary War (1775-1783). It was the decisive action of the First Barbary War (1801-1805), although Eaton was furious over what he called a 'sell-out' between State Department diplomat Tobias Lear and the bey. Hamet returned to Egypt and the mercenaries were never fully paid.
William Eaton returned to the United States as a national hero. Legend holds that O'Bannon was presented a Mameluke sword by Hamet, the Ottoman Empire viceroy. No evidence supports this claim. The first mention of Hamet giving O'Bannon a bejeweled sword seems to be in a lengthy article, "Kentucky Officer First to Carry Stars and Stripes to Victory in Foreign Country," by John Presley Cain in the 29 July 1917 edition of the Louisville Courier-Journal. One sword that was purported to be the sword in question turned out to be a late-Victorian era forgery. He was later awarded a sword of honor by his home state of Virginia. A further legend holds that O'Bannon's exploits in North Africa inspired the Marine Corps officers to adopt Mameluk swords, but this is also uncorroborated by any contemporaneous sources. Swords of this style were very popular in Europe and a more likely scenario is that the Marines were imitating the influential military leaders who were wearing them. The attack on Derna was the inspiration for the lyrics of the Marines' Hymn in the line - "to the shores of Tripoli". The 1950 American film Tripoli starring John Payne, Maureen O'Hara, Howard da Silva is a fictionalized account of the Battle of Derne.