In Norse mythology, Surtr or Surt (Old Norse "black" or "the swarthy one") is an elder jötunn. Surtr is attested in the Poetic Edda, compiled in the 13th century from earlier traditional sources, and the Prose Edda, written in the 13th century by Snorri Sturluson. In both sources, Surtr is foretold as being a major figure during the events of Ragnarök; carrying his bright sword, he will go to battle against the Æsir, he will do battle with the major god Freyr, and afterward the flames that he brings forth will engulf the Earth.In a poem from the Poetic Edda, Surtr is described as having a female companion, Sinmara. In a book from the Prose Edda additional information is given about Surtr, including that he is stationed guarding the frontier of the fiery realm Múspell, that he will lead "Múspell's sons" to Ragnarök, and that he will defeat Freyr. Surtr has been the subject of place names and artistic depictions, and scholarly theories have been proposed about elements of Surtr's descriptions and his potential origins.