Expedition of Mostaganem (1558)

The Expedition of Mostaganem occurred in 1558, when Spanish forces attempted to capture the city of Mostaganem, in modern Algeria, from the Ottomans. The expedition was supposed to be a decisive step in the conquest of the Ottoman base of Algiers, but it ended in failure, and has been called a "disaster".

Background
The harbour of Mostaganem had been captured by the Spanish from the Muslims in 1506. The harbour became part of numerous Spanish possession on the North African coast, which had been captured since 1496: Melilla (1496), Mers-el-Kebir (1505), Oran (1509), Bougie (1510), Tripoli (1510), Algiers, Shershell, Dellys, Tenes.

In 1516, Mostaganem was seized by Hayreddin Barbarossa from his base of Algiers, who then strengthened its defences. The city then became a rival of Oran. From 1519, Barbarossa placed himself under the protection of the Ottomans, thereby transforming Mostaganem into an Ottoman dominion.

Previous Spanish expeditions had taken place in 1543 and 1547, which failed as the Spanish forces were repulsed and then pursued in retreat by Turkish and tribal forces.

The expedition of 1558 to retake Mostaganem from the Ottomans followed a string of Ottoman successes in the Mediterranean, especially with the Siege of Tripoli in 1551, and the evacuation of Al-Mahdiyeh by the Spaniards. Concurrently, the corsairs of Barbary were operating from their base in Algiers.

Ottoman-Moroccan conflict
In 1556, the Ottomans of Algiers had besieged Oran, although unsuccessfully, while in the meantime the Moroccans seized the opportunity to capture Tlemcen from the Turks. In 1557, the Ottomans demanded the submission of Morocco to the Ottoman Empire, but murdered the Moroccan ruler Mohammed ash-Sheikh, who was collaborating with Spain, when he refused.

In March 1558, the Ottomans under Hasan Pasha, the son of Barbarossa and ruler of Algiers, had invaded the Moroccan territory toward Fez, but were stopped at the indecisive Battle of Wadi al-Laban just north of Fes. The Ottomans retreated when they learned about Spanish preparations for an offensive in Oran.

Expedition
An elite contingent, numbering 6,500, was dispatched from Málaga by Philip II of Spain, and concentrated at the Spanish base of Oran to join local Spanish troops and the Moroccan Goum troops of the Caïd of Tlemcen, Abdallah al-Ghalib. They departed from Oran on 22 or 26 August 1558.

The Spanish expedition first successfully managed to capture. They then attacked Mostaganem but were repulsed. With supplies running low, they learnt that Hasan Pasha was arriving from Algiers with a relief force of about 6,000 troops. This led to a panic retreat by the Spanish troops. In the end, around 12,000 Spanish soldiers were taken prisoner. Count Alcaudete, Governor of Oran, died in the expedition. His son Don Martín de Córdoba, himself future Governor of Oran, was also captured in the disaster and would be imprisoned as a Christian slave in Algiers under the beylerbey Hasan Pasha, until he was exchanged for the huge ransom of 23,000 escudos.

The failure of the expedition of Mostaganem ended attempts at a grand alliance between Spain and Morocco against the common Ottoman enemy.