After a successful invasion of Tripoli by Habsburg Spain in 1510, and its handover to the Knights of St. John, the Ottoman admiral Sinan Pasha took control of Libya in 1551. His successor Turgut Reis was named the Bey of Tripoli and later Pasha of Tripoli in 1556. By 1565, administrative authority as regent in Tripoli was vested in a ''pasha'' appointed directly by the ''sultan'' in Constantinople/Istanbul. In the 1580s, the rulers of Fezzan gave their allegiance to the sultan, and although Ottoman authority was absent in Cyrenaica, a ''bey'' was stationed in Benghazi late in the next century to act as agent of the government in Tripoli. European slaves and large numbers of enslaved Blacks transported from Sudan were also a feature of everyday life in Tripoli. In 1551, Turgut Reis enslaved almost the entire population of the Maltese island of Gozo, some 5,000 people, sending them to Libya.