Harald, after concluding peace with Sweyn Estridsson, had set out on his campaign of conquering England from Harold Godwinson in 1066.

Before departing, he had appointed his eldest son Magnus as regent and king of Norway in his absence, and had his younger son Olaf accompany him on the expedition.

After initial success in the Battle of Fulford, Harald had been defeated and killed by Harold Godwinson in the Battle of Stamford Bridge.

Olaf survives and returns to Norway with the remaining troops in early 1067, and is proclaimed king and co-ruler with his brother Magnus.

Although it had been intended for Magnus and Olaf to rule the kingdom jointly without division, in practice Olaf rules over Viken (the southeastern part of Norway), while Magnus controls the Uplands and Trøndelag (the middle parts of Norway) along with Western Norway and Northern Norway.

Despite of this division, there are no signs of hostility between the brothers, and their relationship appears to have been peaceful.