I wonder if this (PDF) was what Bert Lloyd had in mind? According to that article, there's an old Hungarian folk tale of a girl who runs away with a soldier. They rest under a tree; she sits with her back to it while he lies with his head in her lap, after warning her not to look up in the branches of the tree. When he falls asleep she looks up, to find the bodies of eleven girls hanging in the tree. She weeps with fear; her tears drop on his face and wake him up, whereupon he tells her (in so many words) that eleven pretty maidens he's hanged there and the twelfth will surely be her. Apparently there are different versions of how (if?) she gets out of it.

Anyway, there's a picture in that article of a very, very old piece of ornamental metalwork which seems to represent the crucial scene from the story - there's a woman sitting against a tree with a man lying with his head in her lap, and two horses tethered nearby. Conjectural, but interesting.