In Norse mythology, Dvalin was a ruler of the dwarves and one of the most powerful dwarves, known primarily for having invented runes. He also made Sif's golden wig, Gungnir (Odin's spear), Skidbladnir (a ship), Tyrfing, the magic sword and, with Alfrik, Berling and Grer , Freya's incredible Brising necklace, Brísingamen (Freya paid the four craftsmen with four nights in her bed).