Ring-a-round of rosies
Pocket full of posies
We all fall down!
All of us have played that kindergarten game where the kids move around in circles joining hands, singing and falling down with the last line. [Video]
When I was young, and not sure about the exact words, would still sing along making up words. So ring-a-round became ringa ringa, rosies turned to roses, posies transformed to poses and as for the third line, it was just random mumbo-jumbo, which we could never figure out.
Now was reading Dan Brown’s Inferno, where the same song was referenced. One theory (which Dan Brown subscribes to) says that this song was about the Great Plague of 1665 in London. Apparently a "ring around the rosie" referred to the pustules which developed on the skin indicating a plague infection. Posies were flowers carried in the pockets to counter the stench of plague. Victims generally just fell down and died and finally were cremated in a bid to destroy the plague (turning into ashes).
While an interesting theory, it is subject to speculation of being just an urban legend. However, how such a lyric became a children’s play song is certainly beyond my comprehension. Children falling down to enact plague victims’ deaths is quite a dark representation!
Further research on the subject led to snopes.com. They categorically say that this seems a revisionist version of history. There are many versions of the poem with different lines (also explains why I never got the exact words at the time). While the song has been around for centuries, documentary evidence linking it to plague starts appearing only in the middle of the twentieth century. Certainly seems more a case of a theory being fitted to a fact and then the believers taking it up. Dan Brown certainly is known for using lots of symbology in his works all of which are open to interpretation based on your willingness to believe in them.
Overall, the origins are unknown with speculations ranging from simple play-song to church banning dancing to plague. Take your pick.