Twelfth Night

Background
Twelfth Night, or What You Will is a romantic comedy by William Shakespeare, believed to have been written around 1601–1602 as a Twelfth Night's entertainment for the close of the Christmas season. The play centres on the twins Viola and Sebastian, who are separated in a shipwreck. Viola (who is disguised as Cesario) falls in love with Duke Orsino, who in turn is in love with Countess Olivia. Upon meeting Viola, Countess Olivia falls in love with her thinking she is a man.

The play expanded on the musical interludes and riotous disorder expected of the occasion, with plot elements drawn from the short story "Of Apollonius and Silla" by Barnabe Rich, based on a story by Matteo Bandello. The first recorded public performance was on 2 February 1602, at Candlemas, the formal end of Christmastide in the year's calendar. The play was not published until its inclusion in the 1623 First Folio.

Summary
Viola finds herself shipwrecked in Illyria and, assuming that her brother Sebastian has died in the wreck, disguises herself as a man to gain a position in Duke Orsino's court. Orsino sends Viola (whom he knows as Cesario) to deliver a message to his love, Olivia. Olivia, however, dislikes the Duke. She falls in love with Viola, who she thinks is a man. Eventually, Viola's brother Sebastian, who in fact was unharmed in the wreck, reappears. At a critical moment, Viola's true identity is revealed when members of the court notice the similarities between her and Sebastian. Olivia quickly falls in love with Sebastian, and Viola confesses her love for the Duke.

Links to Upstart Crow
Green attempts to trick Shakespeare into wearing "yellow tights and really silly cross-garters" for Lord Southampton's "saucy prancings" so as to ridicule him. This alludes to "Twelfth Night", where Sir Toby Belch, Sir Andrew Aguecheek, and Maria convince Malvolio to wear yellow stockings cross-gartered to impress Olivia, knowing that she hates both such colour and fashion.