Twelfth Night is a comedy by William Shakespeare believed to have been written around 1601-1602. It is set in Illyria and follows the story of twins Viola and Sebastian who are separated during a shipwreck. Viola disguises herself as a man named Cesario and enters the service of Duke Orsino, who sends Cesario to profess his love to Countess Olivia, though Olivia ends up falling in love with Cesario. Meanwhile, several characters conspire to trick Olivia's steward Malvolio into believing Olivia loves him as a means of revenge.