Sveinn of Viken (The Kalmar Union)

After the deaths of two vassal lords ruling Viken on his behalf in quick succession Cnut set his son Sveinn as his regent in Viken in 1030. As a minor it would be his English mother Aelfgifu who effectively ran the country. She was widely disliked however as the authorities attempted to impose punative Danish laws on the land. It also angered several lords who believed Cnut had promised them rulership. Eventually Cnut was forced to invade in 1031 to restore his son to the throne.

Sveinn would rule in his own right from 1032 though was often reliant on Danish forces to keep his throne. He was frequently threatened by lords conspiring with the heirs of the Fairhair dynasty who looked to remove Danish influence from both Viken and Hordaland. Eventually the forces of Magnus I overcame Sveinn's in 1035. Fleeing to Denmark he would die shortly afterwards leaving his inheritance to be fought over between his half-brother Harthacnut (Cnut III) and Magnus.