Harald Sigurdsson (Old Norse: Haraldr Sigurðarson), given the epithet Hardrada (harðráði, roughly translated as "stern counsel" or "hard ruler") in the sagas, was King of Norway (as Harald III) from 1046 to 1066. In addition, he unsuccessfully claimed the Danish throne until 1064 and the English throne in 1066. Prior to becoming king, Harald had spent around fifteen years in exile as a mercenary and military commander in Kievan Rus' and of the Varangian Guard in the Byzantine Empire.
Harald invaded Northern England in September 1066, raided the coast and defeated English regional forces in the Battle of Fulford near York. Although initially successful, Harald was defeated and killed in an attack by Harold Godwinson's forces in the Battle of Stamford Bridge. Modern historians have often considered Harald's death at Stamford Bridge, which brought an end to his invasion, as the end of the Viking Age. Harald is also commonly held to have been the last great Viking king, or even the last great Viking.