 In the Autumn of 1550 Andrea Doria contacted Salih Reis and attempted to convince him for serving Spain instead of the Ottoman Empire, but failed.In June–August 1551, Salih Reis joined the fleet of Sinan Pasha and Turgut Reis, and played an important role in the conquest of Tripoli (Libya), which had been a possession of the Knights of St. John since 1530, when it was given to them by Charles V of Spain.He bombarded the fortress of the Knights from a distance of approximately 150 steps, eventually forcing Gaspare de Villers, their commander, to surrender.