IN marble walls as white as milk,
Lined with a skin as smooth as silk,
Within a fountain colour clear,
A golden sphere doth there appear;
No doors are found in this stronghold,
Yet thieves break in and steal the gold.
First published in John Newbery’s Mother Goose’s Melody in 1765, this rhyme is actually a riddle that the reader is expected to solve. A riddle is an ambiguous statement, or puzzle, that can have several answers, although only one can be correct, and riddles have been popular since ancient times. As long ago as 400 bc, Plato is known to have observed children learning riddles; they feature in Old Norse literature and in Old English poetry, most notably in the Exeter Book – a collection of manuscripts originally housed in Exeter Cathedral – dating from around ad 800. While mostly frivolous, riddles can be profound, and even life-threatening: in perhaps the most celebrated riddle-posing session of all time, Oedipus has to give the correct answer to the Sphinx in order to avoid being killed. While the rhyme above is hardly in this category, in keeping with time-honoured tradition, I’m not going to give you the answer, but I will give you a clue. It’s not the Bank of England, although you might go to work on it. (For other riddling rhymes, see As I Was Going to St Ives and Flour of England.)