Harald Sigurdsson (1015 – September 25, 1066), later given the epithet Hardrada (Old Norse: roughly translated as “stern counsel” or “hard ruler”) was the king of Norway from 1047 until 1066. He also claimed to be the King of Denmark until 1064, often defeating King Sweyn’s army and forcing him to leave the country. Many details of his life were chronicled in the Heimskringla and other Icelandic sources. Among English speakers, he is generally remembered for his failed invasion of England in 1066. Harald’s death at the Battle of Stamford Bridge which brought an end to that invasion is often recorded as the end of the Viking Age.
*excerpt taken from source on wikipedia, which actually has a lot of good references and sources about Harald