Battle of Djerba The naval Battle of Djerba ( ) took place in May 1560 near the island of Djerba , Tunisia in which the Ottomans under Piyale Pasha ' s command overwhelmed a large joint European fleet , chiefly Spanish forces , sinking half its ships . Background . Since losing against Barbarossa Hayreddin ' s Ottoman fleet at the Battle of Preveza in 1538 and the disastrous expedition of Emperor Charles V against Barbarossa in Algiers in 1541 , the major European sea powers in the Mediterranean , Spain and Venice , felt more and more threatened by the Ottomans and their corsair allies . Indeed , by 1558 Piyale Pasha had captured the Balearic Islands and together with Turgut Reis raided the Mediterranean coasts of Spain . King Philip II of Spain appealed to Pope Paul IV and his allies in Europe to organize an expedition to retake Tripoli from Turgut Reis , who had captured the city from the Maltese Knights in August 1551 and had subsequently been made Bey ( Governor ) of Tripoli by Sultan Suleiman the Magnificent . Forces . The historian William H . Prescott reportedly wrote that the sources describing the Djerba campaign were so contradictory that he defied the reader to reconcile them . Anyone attempting to piece together the campaign will be forced to the same conclusion . Most reputable historians believe that the fleet assembled by the allied Christian powers in 1560 consisted of between 50 and 60 galleys and between 40 and 60 smaller craft . For example , Giacomo Bosio , the official historian of the Knights of St John writes that there were 54 galleys . Fernand Braudel also gives 54 warships plus 36 supply vessels . One of the most detailed accounts is by Carmel Testa who evidently has access to the archives of the Knights of St . John . He lists precisely 54 galleys , 7 brigs , 17 frigates , 2 galleons , 28 merchant vessels and 12 small ships . These were supplied by a coalition that consisted of Genoa , the Grand Duchy of Tuscany and the Papal States , and the Knights of S . John . Matthew Carr gives the number of 200 ships for the Christian Alliance . The joint fleet was assembled at Messina under the command of Giovanni Andrea Doria , nephew of the Genoese admiral Andrea Doria . It first sailed to Malta , where bad weather forced it to remain for two months . During this time some 2 , 000 men were lost to sickness . On 10 February 1560 , the fleet set sail for Tripoli . The precise numbers of soldiers aboard are not known . Braudel gives 10 , 000 - 12 , 000 ; Testa 14 , 000 ; older figures in excess of 20 , 000 are clearly exaggerations considering the number of men a sixteenth - century galley could carry . Although the expedition landed not far from Tripoli , the lack of water , sickness and a freak storm caused the commanders to abandon their original objective , and on 7 March they returned to the island of Djerba , which they quickly overran . The Viceroy of Sicily , Juan de la Cerda , 4th Duke of Medinaceli , ordered a fort to be built on the island , and construction was begun . By that time an Ottoman fleet of about 86 galleys and galliots under the command of the Ottoman admiral Piyale Pasha was already underway from Istanbul . Piyale ' s fleet arrived at Djerba on 11 May 1560 , much to the surprise of the Christian forces . The battle . The battle was over in a matter of hours , with about half the Christian galleys captured or sunk . Anderson gives the total number of Christian casualties as 18 , 000 but Guilmartin more conservatively puts the losses at about 9 , 000 of which about two - thirds would have been oarsmen . The surviving soldiers took refuge in the fort they had completed just days earlier , which was soon attacked by the combined forces of Piyale Pasha and Turgut Reis ( who had joined Piyale Pasha on the third day ) , but not before Giovanni Andrea Doria managed to escape in a small vessel . After a siege of three months , the garrison surrendered and , according to Bosio , Piyale carried about 5 , 000 prisoners back to Istanbul , including the Spanish commander , D . Alvaro de Sande , who had taken command of the Christian forces after Doria had fled . The accounts of the final days of the besieged garrison are irreconcilable . Ogier de Busbecq , the Austrian Habsburg ambassador to Constantinople , recounts in his famous " Turkish Letters " that , recognizing the futility of armed resistance , de Sande had tried to escape in a small boat , but was quickly captured . In other accounts , for instance Braudel ' s , he led a sortie on 29 July and was in that way captured . Through Busbecq ' s efforts , de Sande was ransomed and released several years later and fought against the Turks at the Siege of Malta in 1565 . Aftermath . The victory in the Battle of Djerba represented the apex of Ottoman naval domination in the Mediterranean , which had been growing since the victory at the Battle of Preveza 22 years earlier . Of particular importance were the crippling losses of the Spanish fleet in experienced personnel : 600 skilled mariners ( " oficiales " ) and 2 , 400 arquebusier marines were lost , men who could not be quickly replaced . After Djerba the Maltese channel lay open and it was inevitable that the Ottomans soon turned on the new base of the Knights of St John in Malta in 1565 ( the Knights having previously been expelled from Rhodes in 1522 ) , but did not succeed this time . It was not until the Battle of Lepanto in 1571 that the myth of Ottoman naval invincibility ended .