It is a subject of debate whether Otranto was meant to be the base for further conquests. In any case, the Ottoman sultans had not given up their ambition to take over the Italian Peninsula and to finally install Islamic sovereignty after the conquest of Constantinople. After the conquests of Ragusa (Dubrovnik) and Hungary in 1526 and the defeat of the Turkish army at Vienna in 1529, Turkish fleets again attacked southern Italy. Reggio was sacked in 1512 by the famous Turkish corsair Khayr al-Din, better known by the nickname of Barbarossa; in 1526 the Turks attacked Reggio again, but this time suffered a setback and were forced to turn their sights elsewhere. In 1538 they defeated the Venetian fleet. In 1539 Nice was raided by the Barbary pirates (Siege of Nice), but an attempted Turkish landing on Sicily failed, as did the attempted conquest of Pantelleria in 1553 and the siege of Malta in 1565.