text: This man's first wife was Elisaveta, the daughter of Yaroslav the Wise of Kiev.
full_question: This man's first wife was Elisaveta, the daughter of Yaroslav the Wise of Kiev. This king once served as a mercenary in the Byzantine Varangian guards, in one apocryphal story kidnapping Pricess Maria. This one-time co-monarch alongside his nephew, Magnus the Good, gained the throne of Denmark after fighting Sweyn Estridsson until 1064. This man seized York following his defeat of Morcar, the Earl of Northumbira, at the Battle of Fulford, just five days before his final defeat. For 10 points, name this Norweigan king who was defeated by Harold Godwinson at the Battle of Stamford Bridge.
first_sentence: This man's first wife was Elisaveta, the daughter of Yaroslav the Wise of Kiev.