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 entertainment for the close of the Christmas season. The play centres on the twins Viola and Sebastian, who are separated in a shipwreck. Viola (disguised as a page named 'Cesario') falls in love with the 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,[1] with plot elements drawn from Barnabe Rich's short story "Of Apollonius and Silla", based on a story by Matteo Bandello. The first documented 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.
Shakespeare, having tackled the theatrical problems of providing Twelfth Night with effective musical interludes, found his attitude toward his material changed. An episodic story became in his mind a thing of dreams and themes.