“Hey Diddle Diddle” is perhaps the best-known nonsense verse in the English language, about which “a considerable amount of nonsense has been written”. The earliest known version appeared in print in MG’s Melody (c. 1756), although it seems possible that it had been in circulation since at least the 16th century. The rhyme is considered to be the origin of the phrase “over the moon”, meaning “extremely happy”.
The common modern version is:
Hey diddle diddle,
The cat and the fiddle,
The cow jumped over the moon;
The little dog laughed
To see such sport,
And the dish ran away with the spoon.
The word “sport” at the end of the penultimate line is sometimes replaced with “fun” or “craft”, as it did in the 1765 version. The melody commonly associated with the rhyme was written by the English composer and nursery rhyme collector James William Elliott, and published for the first time in his National Nursery Rhymes and Nursery Songs (1870).
In the words of A Dictionary of English Folklore, “Nursery rhymes have suffered the indignity of having more nonsense written about them than any other folklore genre”, and “Hey Diddle Diddle” is no exception. Among the meanings ascribed to the rhyme is that it is a corrupted version of an ancient Greek chorus,[a]Almost certainly a hoax. papist priests urging the labouring class to work harder, a reference to the worship of the ancient Egyptian goddess Hathor, or that it refers to Elizabeth, Lady Katherine Grey, and her relationships with the Earls of Hertford and Leicester. It has also been suggested that the expression “cat and the fiddle” refers to Katharine of Aragon, Katherine la Fidèle, the first wife of King Henry VIII, but all of these hypotheses are now largely discredited.
The image of a cat playing a fiddle was popular in early medieval illuminated manuscripts, and the “Cat and Fiddle” was a common name for inns, including one known to have been at Old Chaunge, London by 1587.