Tweedledum and Tweedledee
The first known mention of Tweedledum and Tweedledee is found in an epigram (1727) by John Byrom. It targets the rivalry of two composers — Georg Friedrich Händel and Giovanni Battista Bononcini — in the London of the 1720s.
The pair appears again in a nursery rhyme (printed around 1805) which may (or may not) have been old enough to be known to Byrom.
The epigram (1927)
An Epigram on the Feuds between Handel and Bononcini
Some say, compared to Bononcini That Mynheer Handel's but a ninny; Others aver that he to Handel Is scarcely fit to hold a candle; Strange all this difference should be 'Twixt tweedle-dum and tweedle-dee.
The nursery rhyme
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.
- Through the Looking-Glass, Chapter Four, Tweedledum and Tweedledee