The fictional protagonist of Shakespeare's The Tempest, Prospero is the rightful Duke of Milan, banished to sea by his usurping brother, Antonio. Prospero and his daughter, Miranda, find refuge on an island, where Prospero learns sorcery from books and uses it to protect his daughter and control the other characters, such as Ariel and Caliban, whom he has enslaved. At the end of the play, Prospero sinks his books in the sea, likely in an effort to appease Shakespeare's audiences, who viewed magic as devilish.