I’m about three years behind the times here, but I just ran across a fascinating study, via this article from The Guardian:
The actual paper is here:
“Comparative phylogenetic analyses uncover the ancient roots of Indo-European folktales”, by Sara Graça da Silva and Jamshid J. Tehrani.
Basically, the authors used the research methods of anthropology and biology, and they traced the existence of various folktales throughout the realm of the Indo-European language distribution (i.e. Europe and into India).
Unsurprisingly (to anyone but top-down theorists), they found evidence for the telling of certain tale types way, way back, before the languages we know today even existed.
The things you find out when you dig around for more info on “Sleeping Beauty” for the retelling you’re working on… (I don’t even know by which rabbit trail I arrived at that article…)