In which battle did the Ottoman fleet under Piyale Pasha defeat a Spanish-led Holy League in 1560? The answer is the Battle of Djerba.
The battle took place in May 1560 near Djerba, an island off the coast of Tunisia. An alliance dominated by Spanish forces, with Genoese, Papal, Neapolitan, Maltese, and other contingents, had captured the island and begun building a fort after abandoning an attempt to attack Tripoli.
An Ottoman fleet of about 86 galleys and galliots, commanded by Piyale Pasha, arrived on 11 May and caught the Christian force by surprise. The Ottomans overwhelmed the alliance, sinking or capturing many vessels and forcing the survivors into a disastrous defense of the unfinished fort.
Djerba is often confused with Lepanto, another famous Ottoman–Christian naval battle. Lepanto occurred in 1571 and ended in a Holy League victory. At Djerba, eleven years earlier, the Ottoman fleet won a major victory that demonstrated the empire’s continued dominance in the Mediterranean.