From the Burgh Records of January 1587, we learn that Edinburgh Town Council starts the new year pragmatically (as do we all) with a bit of a tidy-up, and so:
"Ordanis James Ros, thesaurer, to caus red the rowme of the awld gallows; baynes, deid corssis and all."
["Orders James Ross, treasurer, to have cleared the space around the old gallows; bones, dead corpses and all."]
The past few years had been busy ones for Edinburgh's justice system (never quiet at the best of times), what with continual risings supporting the then-imprisoned Mary, Queen of Scots, and consequently continual executions for rebellion. While high-ranking rebels met their ends through decapitation with great ceremony, those of lesser status were hanged with as little pomp as common criminals, on one of the many sets of gallows positioned in and around the city.
Not only were more people being executed than usual around this period, but once executed their remains were required to be kept on display. As traitors to the Crown, it was traditional to make example of them by leaving them to rot on public display, chained to the gallows to prevent their relatives from stealing them for a dignified burial.
Ordinarily, these gruesome exhibits would be removed only by order of Parliament; otherwise they would simply be allowed to disintegrate. If only a few traitors were on display, scavengers could be relied upon to consume the fleshy parts in relatively short order, and normal foot-traffic would grind what remained into the mud around the gallows foot.
However, as more rebels were executed at an increasing rate, the crows and rats of the Old Town would not trouble themselves to consume one body so completely before moving on to fresher meat. As a result, the ground around the gallows accumulated a rapidly-growing pile of stinking human remains, as the limbs by which the corpses were suspended rotted through, letting the body drop to the ground.
Anticipating a truly stomach-turning scene if this should not be cleared up before warmer weather began (and possibly expecting their gallows to continue doing a brisk trade for the foreseeable future), the council took the wise step of doing its spring cleaning early, and giving the citizens a break from having to walk past a pile of dead rebels every day.
Perhaps fortunately for Edinburgh's residents, Queen Mary would be executed a little over a month after this order was issued, and Scotland enjoyed a relatively quiet period thereafter, with significantly fewer corpses left lying around. It was a short period, but it was definitely slightly less disgusting.