Erling Magnusson was claimed to be an illegitimate son of King
Magnus Erlingsson. He also claimed some years earlier to have been arrested by Swedish King
Knut Eriksson and put in the stone tower on the island of
Visingsö in Lake
Vättern. From there he would have escaped, and for this reason he later carried the nickname
Steinvegg meaning Stonewall. At the death of King
Håkon III of Norway in January 1204, no heirs were known. Håkon was therefore succeeded by his 4-year-old nephew
Guttorm Sigurdsson who subsequently died in August 1204. Members of the Bagler party became convinced that Erling Steinvegg was a son of King
Magnus V of Norway and made him a candidate for the Norwegian throne. King
Valdemar II of Denmark attempted to influence the outcome of the Norwegian succession by leading a Danish fleet of over 300 ships and army to
Viken in support of Erling as pretender to the Norwegian throne. Erling Steinvegg succeeded at the
iron test to show that he was of royal descent. To prove his ancestry, Erling undertook the ordeal in the presence King
Valdemar II of Denmark and subsequently received 35 ships as a gift of him. Afterwards, Erling was taken by the king to
Haugating in
Tønsberg and declared to be king of Norway. When Erling died in 1207, he left two infant sons, Sigurd and his brother. They were passed over by the Bagler, in favour of
Philip Simonsson, who became the new Bagler candidate. Neither Erling Steinvegg nor later his son
Sigurd Ribbung would manage to prevail over the Birkebeiner, the ultimate victors in the power struggle for Norway. The Bagler never achieved control of all of Norway, but rather established their rule in Viken in the district surrounding
Oslofjord in southeastern Norway after 1204. Erling Steinvegg died in March 1207.
Philip Simonsson was made his successor as the next pretender by the
Bagler. ==Historic context==