It struck me the other day that "foul play" is an odd sort of euphemism for murder. "Play"? What kind of play?
The Phrase Finder says Shakespeare probably coined the phrase and used it to mean "unfair behavior." (A search at RhymeZone Shakespeare seems to confirm that that was basically what he meant by it.) That seems plausible enough; I can imagine someone taking this common phrase and sort of jokingly and understatingly using it to refer to murder.
Except that MW11 defines it as "violence; especially: murder" and dates it to the 15th century, at least a hundred years before Shakespeare. Then again, MW3 (unabridged) says "unfair, dishonest, or treacherous conduct or dealing; specifically: violence."
Also, MW11 notes that "play" can mean "swordplay."
Anyway, I'm left without an answer to my question. I'm specifically wondering when and how "foul play" came to refer specifically to murder, as in "he met with foul play" or "there was no evidence of foul play." It's a phrase I associate with murder mysteries and detective stories; could it have entered popular use in this context via Arthur Conan Doyle? Agatha Christie? I don't know.
I suppose it could have started with the line from Pericles: "She died by foul play." But now I'm just guessing. Anyone know for sure?