The Chronicle of The Kings of Norway
Part 4 - Of Thorer Of Steig
"There was a man called Svein, a son of Harald Fietter. He was a Danish man by family, a great viking and champion, and a very clever man, and of high birth in his own country. He had been some time with King Hakon Magnuson, and was very dear to him; but after King Hakon's decease Thorer of Steig, his foster-father, had no great confidence in any treaty or friendship with King Magnus, if the whole country came into his power, on account of the position in which Thorer had stood to King Magnus, and the opposition he had made to him.
Thereupon Thorer and Svein took counsel with each other, which they afterwards carried into effect, — to raise, with Thorer's assistance, and his men, a troop against Magnus. But as Thorer was old and heavy, Svein took the command, and name of leader of the troop. In this design several chiefs took part, among whom the principal was Egil Aslakson of Aurland. Egil was a lenderman, and married to Ingebjorg, a daughter of Ogmund Thorbergson, a sister of Skopte of Giske. The rich and powerful man, Skjalg Erlingson, also joined their party.
Thorkel Hamarskald speaks of this in his ballad of Magnus:
"Thorer and Egil were not wise,
They aimed too high to win a prize:
There was no reason in their plan,
And it hurt many a udalman.
The stone, too great for them to throw,
Fell back, and hurt them with the blow,
And now the udalmen must rue
That to their friends they were so true."
Thorer and Svein collected a troop in the Uplands, and went down through Raumsdal into Sunmore, and there collected vessels, with which they afterwards sailed north to Throndhjem.