A skeleton in the cupboard

First recorded in English in 1816, in an essay discussing family secrets, well before the more American "skeleton in the closet" variant existed. One appealing theory ties it to the early 19th-century medical world: dissection for anatomical study was tightly restricted and unpopular, so doctors who owned an actual human skeleton for teaching purposes sometimes had to keep it hidden away, quite literally a guilty secret behind a cupboard door. It's a neat fit for the period, but no single source confirms this practical explanation over a more general, purely figurative reading of the phrase.