Wikipedia
Elvehøj is the Danish name of a Scandinavian ballad ( Danmarks gamle folkeviser no. 46), known in Swedish as Älvefärd ( Sveriges medeltida ballader no. 31), type A65 ('knight released from elves at dawn') in The Types of the Scandinavian Medieval Ballad; it is also attested in Norwegian.
The ballad is in the first person. The narrator, an attractive young man, falls asleep beside an elf-mound (or elvehøj). Some women (usually elf-maidens) then attempt to woo the narrator, singing so beautifully that the natural world responds (the streams stop flowing, fish dance for joy, etc., depending on the variant). The narrator, however, resists their blandishments, grasping his sword (usually in silence). The man is most often rescued by the crowing of a cock awaking him, though in the Danish A-version, from the mid-sixteenth-century Jens Billes visebog (known to Grundtvig as 'Sten Bille’s Haandskrift'), he is saved by the advice of his sister who, previously enchanted, is one of the elf-maidens. The ballad usually ends with moralising advice to the listeners.
The ballad can be seen as a 'happy ending' version of the much more famous Elveskud. DgF includes five variants of ‘'Elvehøj'’, four from early modern collections. There are three versions in Sveriges medeltida ballader: two (A and C) are complete, with eight four-line stanzas each, while the B-version is fragmentary. Each one is very different from the others. A is the oldest Swedish version, collected in the 1670s from a farmer’s wife in Västergötland; C was collected in Östergötland in the 1840s.
The story is similar to the ballads Herr Magnus och havsfrun, SMB 26, and Jungfrurnas gäst, SMB 30. It was translated into German by Herder (1774), and into English by Lewis (1801) and Jamieson (1806).
The ballad was one of the inspirations for the 1828 patriotic play Elves' Hill (Danish: Elvehøj) by Johan Ludvig Heiberg.