The city of Algiers came into importance in 1510, when the Moors, a group of African Muslims, sought refuge in the city after their expulsion from Spain. The Spanish proceeded to occupy parts of Morocco and Algeria. The emir (ruler) of Algiers called upon the corsair (pirate) brothers Aruj and Khair ad-Din Barbarossa to dispatch the Spaniards who h ad settled there. The brothers were master corsairs and conducted dozens of raids on European vessels and coastal towns and sold their prisoners to slavery. Instead, the brothers arranged for the assassination of the emir and took control of Algiers. Barbarossa took complete control of Algeria after his brother's death, and initiated the annexation of Algeria to the Ottoman Empire in an attempt to protect his kingdom from the Spanish. Upon the annexation of Algeria, Algiers became the principal outpost of the Barbary Pirates. The Barbary Pirates then become instrumental in the expulsion of the Spaniards. In 1541, the Spaniards attempted to capture the city of Algiers, but were defeated by the Ottomans under their pasha (ruler) Hassan.

By the 17th century, Algiers was virtually free from Ottoman rule and pirating became the source of the area's economy. Barbarian (the term is derived from Barbary) pirating raids were different from those conducted by Caribbean pirates. Barbary corsairs worked in teams to intercept European ships, or, raid coastal towns in Italy, France, Portugal, England, Ireland and Spain. The pirates were most interested in capturing people to sell at slave markets throughout the Barbary Coast. Captured slaves were treated miserably and were forced to man the oars of their giant galleys while being whipped and deprived of food. Others were forced into hard labor where they fashioned mud bricks and built fortifications to protect Algiers. Women were often forced to join the harem of the pasha (ruler), which numbered hundreds of women.

1816 Bombardment of Algiers

The Barbary Pirates thrived in Algiers for nearly 300 years. European powers so feared the pirates that they agreed to pay an annual tribute to ensure their vessels sailed through the Mediterranean Sea peacefully. Attempts to subdue the corsairs proved unsuccessful until the United States waged war on the corsairs in the early 1800's after at least one American ship was seized. In 1816, the Barbary Pirates finally met their end when the British general Lord Exmouth and his fleet successfully torched the entire Barbary fleet.