Norway had been divided during the ninth…

Norway had been divided during the ninth century among several local kings controlling their own fiefdoms.

King Harald Fairhair had managed, mainly due to the military superiority gained by his alliance with Sigurd Ladejarl of Nidaros, to subjugate these mini–kingdoms, and by the end of the century he had created the first unified Norwegian state.

This alliance had come apart after Harald's death.

The jarls of Lade and various descendants of Harald Fairhair had spent the tenth century interlocked in feuds over power.

As well as power politics, religion also plays a part in these conflicts, as two of the descendants of Harald Fairhair, Hakon the Good and Olaf Tryggvason attempted to convert the then heathen Norwegians to Christianity.

Svein (Old Norse: Sveinn) and Erik (Old Norse: Eiríkr) of Lade had in the year 1000 taken control of Norway, being supported by the Danish King Svein.

Olaf Haraldsson, representing the descendants of Harald Fairhair, had in 1015 returned from one of his Viking trips and was immediately elected as King of Norway.

He had won the Battle at Nesjar in June 1016 against the Jarls of Lade.

Olaf Haraldsson's success in becoming King of Norway had been helped by the Danes being kept occupied with the ongoing fighting in England.

Olaf II had extended his power throughout Norway while Jarl Erik was with Cnut in England.

Cnut's enmity with him extends further back: Æthelred had returned to England in a fleet provided by Olaf.

Cnut had offered in 1024 to let Olaf govern Norway as his vassal, but after Helgeå, he had set about undermining his unpopular rule with bribes, and in 1028 sets out with fifty ships to subjugate Norway.

A large contingent of Danish ships joins him, and Olaf withdraws into the Oslo Fjord while Cnut sails along the coast, landing at various points and receiving oaths of allegiance from the local chieftains.

Finally at Nidaros, now Trondheim, he is acclaimed king at the Eyrathing, and in a few months Olaf, whose hard-line imposition of Christianity has created powerful enemies within Norway, flees to Novgorod.