Twelve Dancing Princesses folktale type (ATU 306) that I could get my grabby little hands on. It has always been one of my favorite fairy tales, and I love the international collection for it, but this time I was specifically interested in how Hungarian folk storytellers through the ages have interpreted it.
TL; DR: Horribly.
Contrary to the popular Grimm version, Hungarian dancing princesses can number anywhere from 1 to 12; most often there are 3 of them, and in many cases they shred more than one (6-12) pairs of slippers each night. The male protagonist is most often a shepherd or swineherd boy, although the occasional former soldier also appears.
Here is the rundown of how most Hungarian versions go:
1a. The king executes anyone who cannot solve the mystery of the disappearing princesses and shredded shoes. 99 people already have their heads on pikes by the time the protagonist comes along.
1b. The princesses are (all or mostly) evil, and they poison anyone who tries to spy on them.
2. The princesses most often sneak out with older witches, evil fairies, or the Devil himself.
3. They also often dance on razor blades, thus shredding their shoes.
4. There are several versions where (some or all of) the princesses already have children in the Other World, or are pregnant - underlining the assumption that "dancing" is not the only thing they do on their illicit nightly adventures.
5. Once the truth is revealed, almost all tales end with the princesses being executed - most often burned (in cases of witchcraft), beheaded, or torn apart by oxen. Sometimes their bastard children are dragged along with them as well.
(In the few cases where they survive, they are either imprisoned, exiled, or simply not mentioned at all)
6a. Sometimes the youngest (and purest) princess survives and gets to marry the male protagonist (occasionally against her will),
6b. In a surprising number of cases, the guy refuses to marry a "whore" (kurva) and asks for money instead.
There are only 2 versions that I could find where the little princess is actually in love with the shepherd boy before he solves the mystery.
7. The story type often occurs intertwined with the Princess in the Shroud, where the accused princesses die, turn into man-eating vampires, and have to be "redeemed" by same male protagonist. Marriage, once again, is encouraged by optional (on the guy's side, duh).
There is also a mythical/religious element to all this - secret trips into the Other World slowly turning from alluring fairy dances to witches' Sabbaths or journeys to Hell, and girls being punished for the mentorship of older, "sinister" female figures in the art of breaking free of the palace at night.
It is important to note that most of the 15+ versions I read were told by male storytellers (the ones that named the teller, anyway), with three exceptions - including the one that will be featured in my book, because she had a wildly different, more empathic, and girl-friendly take on the whole thing.
With that said: This fairy tale is never going to be the same again.