A central character in Shakespeare's "Twelfth Night," Olivia is a countess admired by Malvolio, Sir Andrew, and Duke Orsino. However, Olivia falls in love with Cesario, the identity with which Viola disguises herself whilst shipwrecked in Illyria. Olivia mistakenly marries Sebastian, Viola's twin brother, and the two are happy, as the twins are extremely similar in looks and personality.