Sigurd Snake-in-the-Eye (Old Norse: Sigurðr ormr í auga) or Sigurd Ragnarsson was a semi-legendary Viking warrior and Danish king active from the mid to late 9th century. According to multiple saga sources and Scandinavian histories from the 12th century and later, he is one of the sons of the legendary Viking Ragnar Lodbrok and Aslaug. His historical prototype might have been the Danish King Sigfred who ruled briefly in the 870s. Norwegian kings' genealogies of the Middle Ages name him as an ancestor of Harald Fairhair and used his mother's supposed ancestry to Völsung in order to create an ancestry between Harald and his descendants and Odin.