The disguise is intended to protect Viola and allow her to search for her brother, Sebastian , in Illyria, the country on the coast...
In Shakespeare's romantic comedy Twelfth Night, Viola, a young woman and the protagonist of the play, goes in disguise as Cesario, a young man.
The disguise is intended to protect Viola and allow her to search for her brother, Sebastian, in Illyria, the country on the coast of the Adriatic Sea where they've been shipwrecked and separated. The disguise is meant to help Viola to make her way in a male-dominated society.
VIOLA. Who governs here?
CAPTAIN. A noble duke, in nature
As in name. ...
VIOLA. Conceal me what I am, and be my aid
For such disguise as haply shall become
The form of my intent. I'll serve this duke ... (1.2.24–25, 56–58)
Shakespeare uses this same device and reasoning in As You Like It. Rosalind, the protagonist, is ordered by her uncle, Duke Frederick, to leave his dukedom. Rosalind's cousin, Celia, suggests that they go to the Forest of Arden to be with Rosalind's father, Duke Senior, who has also been banished.
ROSALIND. Why, whither shall we go?
CELIA. To seek my uncle in the Forest of Arden.
ROSALIND. Alas, what danger will it be to us,
Maids as we are, to travel forth so far?
Beauty provoketh thieves sooner than gold.
CELIA. I’ll put myself in poor and mean attire,
And with a kind of umber smirch my face.
The like do you. So shall we pass along
And never stir assailants.
ROSALIND Were it not better,
Because that I am more than common tall,
That I did suit me all points like a man? ... (1.3.112–123)
The theme of a woman making her way in a male-dominated society also occurs in The Merchant of Venice. Portia, a wealthy heiress, disguises herself as a male lawyer in order to defend the merchant, Antonio, against the money-lender, Shylock.
In Twelfth Night, Viola, as Cesario, finds employment with Duke Orsino, who orders Cesario to woo the Lady Olivia on the Duke's behalf.
It's during her service to Orsino that Viola realizes that her disguise can also lead to unfortunate consequences. Instead of falling in love with Orsino, Olivia falls in love with Cesario. Olivia uses the excuse of allowing Cesario to woo her on Orsino's behalf to woo Cesario herself.
VIOLA. ... She loves me, sure ...
Poor lady, she were better love a dream.
Disguise, I see, thou art a wickedness ...
[M]y master [Orsino] loves her [Olivia] dearly;
And I, poor monster, fond as much on him;
And she, mistaken, seems to dote on me.
What will become of this? As I am man,
My state is desperate for my master's love;
As I am woman,—now alas the day!—
What thriftless sighs shall poor Olivia breathe!
O time! thou must untangle this, not I;
It is too hard a knot for me to untie! (2.2.24–40)
In As You Like It, a similar consequence arises. Once in the Forest of Arden, Rosalind meets Orlando, a young man with whom she fell in love before she was banished by Duke Frederick. Now disguised as Ganymede, Rosalind chooses not to reveal herself to him, and, as Ganymede, she convinces Orlando that Ganymede can teach him how to woo Rosalind properly and win her for his wife.
Rosalind, as Ganymede, also helps Silvius, a shepherd, pursue his love for a local countrywoman, Phebe. Unfortunately, Phebe disdains Silvius, and she falls in love with Ganymede instead.
ROSALIND. [as Ganymede] ... I pray you, do not fall in love with me,
For I am falser than vows made in wine. (3.5.77–78)
Complications naturally ensue, which, as in Twelfth Night, are eventually resolved. Those who are in disguise reveal their true selves. Merry mix-ups are straightened out, order is restored, and everyone—except Malvolio in Twelfth Night, and Silvius in As You Like It—live happily ever after.