Fjölnir (Old Norse: Fjǫlnir, lit. "Manifold" or "Multiplier") is a legendary king in Norse mythology said to have been the son of Freyr (Frey) and his consort Gerðr (Gertha). The name appears in a variety of forms, including Fiolnir, Fjölner, Fjolner, and Fjolne. He was claimed as the progenitor of the Swedish Yngling dynasty, reigning from Gamla Uppsala. According to the Grottasöngr, Fjölnir lived from the 1st century BC to the early 1st century AD.
Fjölnir was said to have drowned in a vat of mead while visiting Peace-Fróði, a similarly-legendary king of Zealand, the Danish island. Fjölnir was then succeeded by his son Sveigðir.
Grottasöngr informs that Fjölnir was the contemporary of Caesar Augustus (63 BC – AD 14). He was a mighty king and the crops were bountiful and peace was maintained. At his time, King Fróði, the son of Friðleifr, ruled in Lejre in Zealand. Grottasöngr relates that when Fróði once visited Uppsala he brought two giantesses, Fenja and Menja:
However, the two giantesses were to be his undoing (see Grottasöngr).