Olaf, a son of Gudbrand Skafhaug, and Maria, a daughter of King Eystein Magnuson, were brought up in the house of Sigurd Agnhot in the Uplands.
While Earl Erling was in Denmark (A.D. 1166), Olaf and his foster-father gathered a troop together, and many Upland people joined them; and Olaf was chosen king by them.
They went with their bands through the Uplands, and sometimes down to Viken, and sometimes east to the forest settlements; but never came on board of ships. Now when, Earl Erling got news of this troop, he hastened to Viken with his forces; and was there in summer in his ships, and in Oslo in autumn (A.D. 1167) and kept Yule there.
He had spies up the country after this troop, and went himself, along with Orm, the King-brother, up the country to follow them. Now when they came to a lake called.... ....  they took all the vessels that were upon the lake.
Footnotes and references:
The name of the lake not given.