Sif, in Norse mythology, was the beautiful second wife of Thor, celebrated on account of her wonderful blonde hair, which the evil Loki cut off on one occasion while she slept. Thor compelled him. on peril of his life, to procure golden hair for Sif instead of that which he had stolen, and Loki, obtained it from the dwarfs. Sif had been previously married, and had given birth to a son, Ullar; Thor's children by her were named Thrudr and Lorride. Sif would appear to have been the most virtuous of the sins, for when Loki, at, Aeger's banquet, charged upon the women and virgins their numerous loves, he spared Sif such exposure. She handed; him a cup while thanking him for his forbearance; upon which he replied that he must concede to her an eminence above all others, since she had possessed only one lover, who was himself.