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 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 Comedy of Errors is one of William Shakespeare's early plays. It is his shortest and one of his most farcical comedies, with a major part of the humour coming from slapstick and mistaken identity, in addition to puns and word play. It has been adapted for opera, stage, screen and musical theatre numerous times worldwide. In the centuries following its premiere, the play's title has entered the popular English lexicon as an idiom for "an event or series of events made ridiculous by the number of errors that were made throughout".