from the Oxford Companion to English Literature, ed. Margaret Drabble:
Twelfth Night, or What You Will, a comedy by *Shakespeare probably written 1601. John *Manningham saw a performance of it in the Middle Temple in February 1602; it was frist printed in the *Folio of 1623. Shakespeare's immediate source for the main plot was 'The History of Apolonius and Silla' in Barnabe *Rich's Riche His Farewell to Militarie Profession (1581). This is derived from Belleforest's version, which by way of *Bandello can be traced back to a Sienese comedy Gl'Ingannati (The Deceived), written and performed 1531.
Sebastian and Viola, twin brother and sister and closely resembling one another, are separated in a shipwreck off the coast of Illyria. Viola, brought to shore in a boat, disguises herself a youth, Cesario, and takes service as page with Duke Orsino, who is in love with the lady Olivia. She rejects the duke's suit and will not meet him. Orsino makes a confidant of Cesario and sends her to press his suit on Olivia, much to the distress of Cesario, who has fallen in love with Orsino. Olivia in turn falls in love with Cesario. Sebastian and Antonio, captain of the ship that had rescued Sebastian, now arrive in Illyria. Cesario, challenged to a duel by Sir Andrew Aguecheek, a rejected suitor of Olivia, is rescued from her predicament by Antonio, who takes her for Sebastian. Antonio, being arrested at that moment for an old offence, claims from Cesario a purse that he had entrusted to Sebastian, is denied it, and hauled off to prison. Olivia coming upon the true Sebastian, takes him for Cesario, invites him to her house, and marries him out of hand. Orsino comes to visit Olivia. Antonio, brought before him, claims Cesario as the youth he has rescued from the sea; while Olivia claims Cesario as her husband. The duke, deeply wounded, is bidding farewell to Olivia and the 'dissembling cub' Cesario, when the arrival of the true Sebastian clears up the confusion. The duke, having lost Olivia, and becoming conscious of the love that Viola has betrayed, turns his affection to her, and they are married.
Much of the play's comedy comes from the sub-plot dealing with the members of Olivia's household: Sir Toby Belch, her uncle, Sir Andrew Aguecheek, his friend, Malvolio, her pompous steward, Maria, her waiting-gentlewoman, and her clown Feste. Exasperated by Malvolio's officiousness, the other members of the house make him believe that Olivia is in love with him and that he must return her affection. In courting her he behaves so outrageously that he is imprisoned as a madman. Olivia has him released and the joke against him is explained, but he is not amused by it, threatening, 'I'll be reveng'd on the whole pack of you.'
The play's gentle melancholy and lyrical atmosphere is captured in two of Feste's beautiful songs, 'Come away, come away, death' and 'When that I was and a little tiny boy, / With hey, ho, the wind and the rain'.
Twelfth Night (1996 film version, dir. Trevor Nunn):
Twelfth Night, dir. Kenneth Branagh: