Tweedledum and Tweedledee

Tweedledum and Tweedledee are characters in an English nursery rhyme and in Lewis Carroll's 1871 book Through the Looking-Glass, and What Alice Found There. Their names may have originally come from an epigram written by poet John Byrom. The nursery rhyme has a Roud Folk Song Index number of 19800.

The names have since become synonymous in western popular culture slang for any two people whose appearances and actions are identical.