The theme of illusion plays an important role throughout William Shakespeare's Twelfth Night, especially since the play is a fantasy, and things are often illusions and rarely what they seem to be. One form of this illusion is disguise, that is people appearing to be one thing whilst in reality another. Examples throughout the play include the disguise in which Viola undertakes when she dresses as Cesario, and also that of Sebastian, who for a time, is believed to be Viola. There are also many other forms of illusion including that of Orsino's love for Oliva, when in reality he is in love with the idea of love, and Olivia's overindulgent mourning for her late brother, described as "The element itself, till seven years' heat, Shall not behold her face at ample view." These lines show the excess of Olivia's mourning. However, perhaps greater than these forms of...