The link between clothing and identity is a theme in many Shakespearean plays, Twelfth Night being an obvious case. Throughout the play, clothing influences how characters interact with each other, and how characters see themselves.
The most obvious instance of this is the case of Viola. Upon her rescue from the shipwreck and the realization of her precarious situation as a single woman in an unfamiliar land, Viola dons the clothing of a man to take on the identity of Cesario. She does this to distance herself from the profound loss of her brother, for safety reasons as a foreigner, and to aid in her plot to find her way into a noble household. As she tells the captain who rescued her ” For such disguise as haply shall become./The form of my intent”(I.i.58-59), meaning that with her new clothing, she can recreate her identity at her will. In this regard she is successful; disguised as Cesario, she quickly rises to the position of Orsino’s page, and is set to work wooing Olivia. Such is the power of her change of clothing that none of the characters, except perhaps Feste, notice that she is a woman, with Olivia falling in love with her and Orsino placing his trust in her. So great is this assumed identity that at the end of the fifth act, even after Sebastian enters the action and Cesario’s true identity is revealed, Viola insists she is Cesario until she changes her clothing. As she tells Orsino, “But this my masculine usurped attire,/Do not embrace me till each circumstance. Of place, time, fortune, do cohere and jump./That I am Viola” (V.i.265-8). In this scene, Viola is stating that her masculine attire completely overpowers her feminine sex, and as such any embracing would be inappropriate between her and the duke. In these ways Viola demonstrates the power of clothing.
The theme of clothing and identity is continued by the prank played on Malvolio by Sir Toby and the others. It is telling that part of their joke is tricking Malvolio into wearing the yellow stockings and cross garters Olivia detests. By this simple chnage in dress, Malvolio is seen as exceptionally unpleasant by Olivia, leading to his eventual medieval institutionalization. Another example of foolish clothing comes in the form of Sir Andrew, in the repeated reference to the “bloody coxcomb.” Apart from being a word for his head, a coxcomb is a hat worn by the fool, and its reference in relation to Sir Andrew is apparent; a boisterous drunk, having been taken advantage of by Sir Toby, is quite the fool. In these ways, clothing and identity are intricately linked through Twelfth Night.