Prince Hat under the Ground (Swedish: Prins Hatt under jorden) is the Swedish version of an old Scandinavian fairy tale. The Norwegian version is called East of the Sun and West of the Moon (Norwegian: Østenfor sol og vestenfor måne).
It was collected in Småland or Blekinge by Gunnar Olof Hyltén-Cavallius and George Stephens and published in Svenska folksagor och äfventyr (1:1-2, 1844-49). It has been filmed on several occasions and forms the basis of Erik Bergman's opera Det sjungande trädet.[1]
It is of the Aarne-Thompson-Uther type 425A, "The Monster as Bridegroom", of the cycle about "the search for the lost husband". The themes of marriage to the monstrous or mysterious husband, of curiosity inspired by the mother, and even the drops of spilled tallow are very similar to the Hellenistic romance of Cupid and Psyche.