In Norse mythology, Fenrir (Old Norse: "fen-dweller"), Fenrisúlfr (Old Norse: "Fenris wolf"), Hróðvitnir (Old Norse: "fame-wolf"), or Vánagandr (Old Norse: "the monster of the river Ván") is a monstrous wolf. Fenrir is attested in the Poetic Edda, compiled in the 13th century from earlier traditional sources, and the Prose Edda and Heimskringla, written in the 13th century by Snorri Sturluson.