The document provides an overview of mistaken identity in Shakespeare's play "Twelfth Night". It notes that the protagonist Viola disguises herself as a man named Cesario after being shipwrecked. Both Orsino and Olivia fall in love with Cesario, not realizing it is actually Viola in disguise. Additionally, Viola's twin brother Sebastian, who she believes to be dead, also appears. The play explores themes of gender, identity, and sexuality through these instances of mistaken identity and disguise.