One of the most popular interpretations of "Ring Around the Rosie" - originally called "Ring o' Roses" - links the lyrics to the bubonic plague that struck England in 1665 (or possibly even the first outbreak of the Black Death in the 1300s).
Ring-a-ring-a-roses A pocket full of posies Ashes! Ashes! We all fall down
Over 20 percent of London's population was wiped out by the Great Plague and the rhyme supposedly describes the victim's onset of symptoms and subsequent death. The "ring-a-roses" refers to a rosy rash, the "pocket full of posies" is the handful of herbs and other spices used to ward of disease and the "ashes" are the cremated remains of the dead. Other versions replace "ashes" with "a-tishoo!" to represent another symptom of the disease: sneezing. Folklorists like Iona and Peter Opie, who penned the Oxford English Dictionary of Nursery Rhymes, doubt the grim connection. For starters, it appeared 200 years too late in Kate Greenaway's 1881 edition of Mother Goose.
The Opies point out a more lighthearted possibility: in Dutch folklore, gifted children are said to be able to laugh roses.
Besides being one of the most enduring nursery rhymes, "Ring Around the Rosie" also shares a part of early cinematic history. It inspired a movie short in 1897 that depicted a group of children playing the game (clasping hands and circling around before they "all fall down"). A 2006 horror movie starring Tom Sizemore also bears the same name but has little to do with the actual rhyme. It's biggest claim to fame outside of the storybooks, however, was in 1947's Living in a Big Way when Gene Kelly used it in a song-and-dance number.
This rhyme is listed in the Roud Folk Song Index at #7925.