Suleiman won the contest for mastery of the Mediterranean, in spite of Christian victories such as the conquest of Tunis in 1535. The regular Ottoman fleet came to dominate the Eastern Mediterranean after its victories at Preveza in 1538 and Djerba in 1560 (shortly after Charles's death), which severely decimated the Spanish marine arm. At the same time, the Muslim Barbary corsairs, acting under the general authority and supervision of the sultan, regularly devastated the Spanish and Italian coasts and crippled Spanish trade. The advance of the Ottomans in the Mediterranean and central Europe chipped at the foundations of Habsburg power and diminished Imperial prestige.