Olaf I of Viken (The Kalmar Union)

Olaf I Geirstadalf was the first king of a united Viken. Previous kings had either ruled only over smaller sub-kingdoms, or over the entire Norwegian lands.

Olaf's Soon after he came of age he had been granted the sub-kingdom of Vingulmark by his father Harald Fairhair. This was the heartland of the Fairhair territories and, although his elder half-brother Eirik was designated heir to the entire Kingdom of Norway, Olaf (and his brother Bjorn Farmann in Vestfold) was the main source of authority in eastern Norway. Indeed Olaf's reign in Viken is usually back-dated to his father's death in 930 rather than 934 when his sole rule was recognised. When Eirik violently tried to break this authority Olaf and Bjorn reacted. Bjorn was killed by Eirik's men in 934 leading to a rebellion against Eirik's rule and the Battle of Haugar. Eirik was defeated and his western lands were soon under the sway of another brother, Haakon. Eirik fled to Jorvik leaving Olaf ruling over eastern Norway, or Viken.

The Olafskvæði almost immediately singles Olaf out as a wise and just king, however Gothenlandic sources suggest he quickly fell out with his remaining sub-kings, including his brothers Halvdan Hålegg and Ragnar Rykkel. Halvdan Hålegg was killed in battle while Ragnar Rykkel would flee to Gothenland and would later opportunistically invade Viken toward the end of Tryggve Olafsson's reign.

Relations with Haakon also broke down as the lords on their borders played the two off against each other to effectively escape taxation by either. The two clashed repeatedly but neither could get the better of the other. Haakon would outlive Olaf however and as Tryggve's reign became ever more bogged down in intermiable warfare Denmark and their Hordalandic allies slowly gained the upper hand.