Ring around the Rosie,
Pockets full of posy,
We all fall down.
Or some version of it anyways.
Pretty much every-time this rhyme comes up, someone points out that it's all about the Black Death. Or the Plague. Or something similarly quasi-disease related.
Because children's rhymes are totally the best source of historical accuracy.
Ring dances were certainly very popular in the Medieval period, they show up in period stories all the time. Usually with some sort of magic, curse, or intrigue (because Medieval-era stories are chock full of those kind of plots). Think of them as a kind of square dance... but without the square bits or polka music.
1656 engraving of a Plague Doctor by Paul Fürst.
Note: Doctors didn't wear this in Medieval times, but they should have, if only because it looks fantastic.
The usual given explanation is that the "ring around the rosie" represents the roundish shaped rose colored rash, the "pockets fully of posy" is the flowers people carried in their pockets to ether ward off the plague or to cover the smell of the dead, the "ashes" is the people who died of the plague being cremated -- or it's the sound of the victims coughing -- and then "we all fall down" when everyone dies.
But, sadly, this particular rhyme doesn't go with a Medieval round dance... or anything, Medieval really. The earliest version wan't written in the 14th or 15th centuries. It wasn't even written during the Renaissance. It was written in 1881 and went like this:
A pocket full of posies;
Hush! hush! hush! hush!
We're all tumbled down. [*]
The plague symptoms that the rhyme supposedly describes? Most of them aren't there in the first version, but on top of that, the symptoms of both the Black Death and Bubonic Plague (although it's commonly held that the Black Death was a variety of Bubonic Plague, the symptoms aren't identical) don't match the rhyme at all. Rashes aren't a common symptom of plague. Nor is sneezing. And most of the dead's bodies weren't burned, but buried in common graves or disposed of in other ways. (Do you have any idea how much wood it would take to burn that many dead bodies?)
And what on earth is a posy? When I asked as a child, I was assured by the All Knowing Teacher that a posy was a kind of flower that grows in England. (It's not. A posy is either a small bouquet of flowers or a motto/inscription on something small and easily ported -- ie, easily carried in a pocket[**]).
So, what is boils down to is that if the Ring Around the Rosie rhyme was about the Black Death or the Plague, then it was orally transferred down for over 300 (possibly 500!) years, in secret, without anyone writing it down, and while getting the symptoms wrong.