Q From Helen Roberton: I know that Mare’s nest means something untidy, but what I’m puzzled by is the idea that mares a) have nests and b) are untidy. Neither seems to accord with reality, and I wonder how this phrase came to be.
A Perhaps it’s because I spend a lot of time nosing around in pre-twentieth-century literature, but my first response to mare’s nest is that it means an illusory discovery. It took a moment to recall that for most people today, when it turns up at all, it does indeed refer to a muddle or a confused situation.
The idea behind the older sense of the phrase was clearly enough a joke, since mares notoriously do not make nests, and so something described as one cannot exist. The first form was to find a mare’s nest, to imagine that one has found something wonderful that turns out not to be real. It’s first recorded in a play in 1576. A typical usage is in Erskine Childers’ The Riddle of the Sands of 1903: “To accept the suggestion we must declare the whole quest a mare’s nest from beginning to end; the attempt on Davies a delusion of his own fancy, the whole structure we had built on it, baseless.”
It’s one variation on a set of phrases that were around centuries ago. Another version was horse’s nest, which was at one time also a dialect term for an idle tale or an oft-told story, one therefore over-elaborated and unbelievable. Other variations that have been recorded include salmon’s nest, and skate’s nest. For some reason, mare’s nest conquered the opposition and became standard. There’s a lovely enlargement of it in the 1811 edition of Captain Grose’s Dictionary of the Vulgar Tongue: “He has found a mare’s nest, and is laughing at the eggs; said of one who laughs without any apparent cause.”
The modern sense wasn’t recorded in the First Edition of the Oxford English Dictionary, the entry for which was compiled in 1904, suggesting that it was then uncommon. The updated online version has examples dating from the 1830s, but the early ones have the sense of “misconception” or “misunderstanding”. My archive search suggests that the untidiness sense began to appear regularly in print only in the 1930s but was common by the 1940s (the OED’s first unambiguous instance of this sense dates from 1948). In Agatha Christie’s The Mysterious Affair at Styles of 1920, the expression appears twice, first in the old sense (“In my opinion the whole thing is a mare’s nest of Bauerstein’s! ... Poisons are his hobby, so of course he sees them everywhere.”), then later in what looks very much like the newer one of a muddle or confusion (“I’m much obliged to you. A pretty mare’s nest arresting him would have been.”).
How the one sense changed into the other isn’t altogether obvious. A progression through illusion to misconception to confusion to muddle to extreme untidiness seems to have occurred. It may be that it was influenced by rat’s nest, a byword for untidiness that’s older than the modern sense of mare’s nest.