Ruffiano and Sweeteeth(1997)

Original title: Lotrando a Zubejda

Famed outlaw Lotrando sends his son to a strict Catholic boarding school to learn manners, but the boy becomes too polite to lead the band. When they inadvertently arrive in a sultanate where the princess Zubeida lies gravely ill and are mistaken for physicians, father and son must overcome their inexperience and imposture to heal her and save the realm.