Inge I
Sigurd Sigurdsson was reportedly a bastard son of King Sigurd II of Norway. He must have been born some time before 1155, when his father was killed in a battle with his half-brother King Inge I of Norway. Sigurd was fostered by Markus of Skog in Ringsaker apparently in Hedmark, due to which his nickname was "Markusfostered".