Ah, the genesis of the "oral tradition." Who knows when the first humans found that there was entertainment value in shared song? Putting local news to music and spreading it from village to village was known to have occurred in England in the middle ages, and probably long before; perhaps on the continent as well. It may date to the Cro Magnon people and....

The other question to ask is, when did someone start calling it "folk music?" There have been compilations of historical ballads, but I can't recall the first reference using the word "folk" in the title. Perhaps one of you musical biblio-tekkies out there can assist.