Sif is the golden haired Norse goddess of wheat and prosperity. She is also the wife of Thor and mother to their daughter Þrúðr. She has a son, Ullr from her previous relationship, which is relatively obscure. Not much is known about Sif, save that she was very vain until her hair was shorn by Loki as a practical joke. Her hair was restored to her by the two Dwarf son's of Ivaldi when Loki goaded them into a bet against the Dwarfs Brokk and Eitri . In the prose 'Loki's Flighting' it is alluded to that she may have had an affair with the trickster god Loki but it is never mentioned in any other prose.
In the 2010 Thor film she is referred to as Lady Sif, and has black hair instead of golden.