The Queen of the Pirates (1960)

In 16th century Italy, on the Adriatic coast, the duchy of Doruzza is governed by a despotic duke, Zulian, and his haughty daughter, Isabella. When they try to commit a gross injutice against one of their subdits, the naval officer Mirko and his daughter Barbara get in their way, and end up persecuted and arrested. The count Cesar de Santacroce, Isabella's fiancee, intercedes for them, and they are set free - only to be arrested again by the treacherous Isabella. Isabella (who felt jealous of Sandra's beauty) dispatches her for slavery in the Middle East. Mirko escapes from his attackers, and manages to get control of the ship, and to free his daughter, who quickly becomes the queen of the Adriatic pirates. That will bring Cesare to a difficult choice between two different kinds of beauty, Isabella the powerful or Barbara the bountiful...