Rafael Sabatini - Sea Hawk

The Sea Hawk is a novel by Rafael Sabatini, originally published in 1915. The story is set in the late 16th century, and concerns a Cornish sea-faring gentleman, Sir Oliver Tressilian, who is villainously betrayed by a jealous brother. After being forced to serve as a slave on a Spanish galley, Sir Oliver is liberated by Barbary pirates. He joins the pirates under the name «Sakr-el-Bahr», the hawk of the sea, and swears vengeance against his brother. (Summary from Wikipedia)