Þrymskviða (Þrym's Poem; the name can be anglicised as Thrymskviða, Thrymskvitha, Thrymskvidha or Thrymskvida) is one of the best known poems from the Poetic Edda. The Norse myth had enduring popularity in Scandinavia and continued to be told and sung in several forms until the 19th century.
In the poem Þrymskviða, Thor wakes and finds that his powerful hammer, Mjöllnir, is missing. Thor turns to Loki first, and tells him that nobody knows that the hammer has been stolen. The two then go to the court of the goddess Freyja, and Thor asks her if he may borrow her feather cloak so that he may attempt to find Mjöllnir. Freyja agrees, saying she would lend it even if it were made of silver and gold, and Loki flies off, the feather cloak whistling.
In Jötunheimr, the jötunn Þrymr sits on a burial mound, plaiting golden collars for his female dogs, and trimming the manes of his horses. Þrymr sees Loki, and asks what could be amiss among the Æsir and the Elves; why is Loki alone in the Jötunheimr? Loki responds that he has bad news for both the elves and the Æsir: that Thor's hammer, Mjöllnir, was gone. Þrymr says that he has hidden Mjöllnir eight leagues beneath the earth, from which it will be retrieved if Freyja is brought to marry him. Loki flies off, the feather cloak whistling, away from Jötunheimr and back to the court of the gods.
Thor asks Loki if his efforts were successful, and that Loki should tell him while he is still in the air as "tales often escape a sitting man, and the man lying down often barks out lies". Loki states that it was indeed an effort, and also a success, for he has discovered that Þrymr has the hammer, but that it cannot be retrieved unless Freyja is brought to marry Þrymr. The two return to Freyja, and tell her to dress herself in a bridal head dress, as they will drive her to Jötunheimr. Freyja, indignant and angry, goes into a rage, causing all of the halls of the Æsir to tremble in her anger, and her necklace, the famed Brísingamen, falls from her. Freyja pointedly refuses.