Act IV, Scene I of Shakespeare’s Twelfth Night, opens with an encounter between Feste the Clown and Sebastian, Viola’s twin brother. Feste mistakes Sebastian for Cesario, who is really Viola in disguise. Feste brings Sebastian to Olivia’s house where they encounter Sir Andrew. Sir Andrew attacks Sebastian, also believing him to be Cesario. Sebastian, overcome by confusion, asks “Are all the people mad?” and attempts to leave (4.1.27). However, before he can retreat, Sebastian is apprehended by Sir Toby. As the men prepare to fight, Olivia enters and demands her uncle, Sir Toby, put away his sword. She begs Sebastian, who she also thinks is Cesario, to come into her house and she offers the following words of consolation: “I prithee, gentle friend, / Let thy fair wisdom, not thy passion, sway / In this uncivil and unjust extent / Against thy peace” (4.1.52-55).

The importance of this scene rests on this first encounter between Olivia and Sebastian. Olivia, who is desperately in love with Cesario, mistakes Sebastian for her lover. Their encounter completes the four angles of the love plot (Olivia / Sebastian, Viola / Orsino). Olivia’s words, “Let thy fair wisdom, not thy passion, sway” are ironic for two reasons. First, the irony lies in Olivia’s own mistake. Guided solely by passion, she mistakes Sebastian for Cesario and soon after marries Sebastian under this mistaken identity. Thus, Olivia does not follow her own advice; she is swayed by passion over wisdom. Similarly, Sebastian also reveals his own impulse toward passion. He is quick to fight both Sir Andrew and Sir Toby. This is, in no small part, due to the confusion he encounters as part of the mistaken identity. Additionally, Sebastian does not question Olivia but, instead, allows himself to be “ruled” by passion and follows Olivia’s lead without question (4.1.64).