By 1559 Dragut was causing the Christian powers such distress, even raiding the coasts of Spain, that Philip II organized the largest naval expedition in fifty years to evict the corsair from Tripoli. The Knights joined the expedition, which consisted of about 54 galleys and 14,000 men. This ill-fated campaign climaxed in the Battle of Djerba in May 1560, when Ottoman admiral Piyale Pasha surprised the Christian fleet off the Tunisian island of Djerba, capturing or sinking about half the Christian ships. The battle was a disaster for the Christians and it marked the high point of Ottoman domination of the Mediterranean.