Sweyn Forkbeard

In the mid-980s Swein turned on his father Harald Bluetooth, seized the crown, and drove the old king into exile where he died in 986 or 987. By 1000 he controlled most of Norway through alliance with Eric, Earl of Lade. His long campaign against England finally succeeded in 1013 when he took the throne, but he died on 3 February 1014, barely five weeks into his reign. His children included Cnut the Great, who would finish what his father started.