The island of Lésbos, in the Aegean Sea, is now part of Greece, but between 1462 and 1912, it lay under Turkish dominion. During the 1470s Lésbos was the birthplace of one of the Ottoman Empire’s greatest heroes. The Mediterranean pirate who would ultimately be remembered as Barbarossa (Italian for “Redbeard”) went by many names during his career: Khiḍr, Hayreddin Pasha, the “Pirate of Algiers,” and even the “King of the Sea,” but the name Barbarossa began as an appellation for him and his brother ʿArūj (or Oruç)—the Barbarossa brothers.

The Barbarossa brothers were already experienced pirates in the Mediterranean when Spain completed its conquest of Granada in 1492, defeating the last vestige of Islamic rule in the Iberian Peninsula, and Muslim immigrants from the region took refuge in North Africa. By 1505 the Spanish and the Portuguese were looking to make territorial gains in North Africa, and they began to attack coastal cities. Enraged by these attacks on fellow Muslims, Khiḍr and ʿArūj served as privateers under the direction of Korkud (one of the sons of the Ottoman sultan Bayezid II) to disrupt Spanish and Portuguese shipping in the western Mediterranean. The sultan’s death in 1512, however, spawned a succession fight between his sons Ahmed and Selim. Selim defeated Ahmed and began a purge of Ahmed’s supporters. Selim was also distrustful of Korkud, and he executed him. In response, the Barbarossa brothers fled to North Africa to separate themselves from a government that likely would have been hostile to them, and they joined the region’s various kingdoms in their struggles against Spain.

Over the next three years, the Barbarossa brothers rose in prominence among the North African communities and preyed on Spanish and Portuguese shipping as independent corsairs. In 1516, forces under the brothers’ command attacked Algiers, and the city fell to ʿArūj. The Ottomans recognized this development as an opportunity to expand their influence in North Africa, and they offered their funding and political support to the brothers (which allowed ʿArūj and Khiḍr to consolidate their gains). The Ottomans then offered the nominal titles of governor of Algiers to ʿArūj and chief sea governor of the western Mediterranean to Khiḍr, but the brothers were not yet full-fledged subjects of the Ottoman Empire.

ʿArūj died battling the Spanish in 1518, and the Spanish recaptured Algiers the following year. During this period, Khiḍr (now known as Hayreddin) assumed the title Barbarossa and stepped up to continue the fight, for which he sought help from the Ottomans. Although Algiers changed hands several times over the next decade, the region it controlled became known as the Regency of Algiers, the first corsair state, which was autonomous but grew more and more dependent upon the Ottoman military for protection over time. The Ottomans would later use Algiers as their primary base of operations in the western Mediterranean.

Barbarossa’s formal association with the Ottomans grew over the same period. Süleyman the Magnificent, who had become sultan after Selim’s death, captured Rhodes in 1522 and installed Barbarossa as the beylerbeyi (governor). After Barbarossa and his forces captured Tunis in 1531, Süleyman made him the grand admiral (kapudan pasha) of the Ottoman Empire, and he served as admiral in chief of the Ottoman navy.

Perhaps Barbarossa’s most famous battle was his victory at Preveza (in Greece) in 1538 over a combined fleet with elements from Venice, Genoa, Spain, Portugal, Malta, and the Papal States. The key to his victory was his use of galleys instead of sailing ships. Because galleys were driven by oars and thus did not depend on the wind, they were more maneuverable and reliable on the sides of bays and islands shielded from the wind than sailing ships were. Barbarossa defeated the combined force by using only 122 galleys against 300 sailing ships. His victory opened Tripoli and the eastern Mediterranean to Ottoman rule. After Barbarossa led additional military campaigns, including one in which he assisted the French against the Habsburgs in 1543 and 1544, he died in Constantinople in 1546.