Tweedledum and Tweedledee are nursery rhyme characters who first appear in print in Original Ditties for the Nursery, published by John Harris in about 1805.[1] In the popular imagination they are most closely associated with the characters of the same name encountered in Lewis Carroll’s book Through the Looking-Glass, and What Alice Found There (1871). Today the names are commonly used to characterise two people or things that are indistiguishable.[2]

The common version of the rhyme reads:[3]

Tweedledum and Tweedledee
Agreed to have a battle;
For Tweedledum said Tweedledee
Had spoiled his nice new rattle.

Just then flew down a monstrous crow,
As black as a tar-barrel;
Which frightened both the heroes so,
They quite forgot their quarrel.

See caption
John Tenniel’s illustration from Through the Looking-Glass (1871)
Wikimedia Commons

The names Tweedle-dum and Tweedle-dee are included in a satirical verse dating from 1725 by the poet John Byrom, suggesting that the nursery rhyme may have been well known before that time. Byrom was writing about a bitter feud between the composers George Frederick Handel and Giovanni Bononcini, in which it was difficult for disinterested observers to discern what the two were disagreeing about.[4] His verse ends with the couplet:

Strange all this Difference should be
‘Twixt Tweedle-dum and Tweedle-dee![4]

Tweedledum and Tweedledee are also obsolete terms used to describe a low or a high-pitched instrument, or the musician who plays it.[2]