[1] Erling Vidkunsson was born into a noble family of Bjarkøy which held lands principally in northern Norway.
He inherited Giske from his uncle Bjarne Erlingsson (1250–1313) upon the death of that man's childless daughter Kristin who died young.
Magnus was acclaimed as hereditary king of Norway at the Haugating in Tønsberg in August 1319 under the regency of his mother, Ingeborg Håkonsdotter.
During the years 1323-31, Erling Vidkunsson led the Norwegian State Board of Royal Authority (norske riksstyret med kongelig myndighet) and held the title of drottsete until Magnus was declared to have come of age at 15.
Although the young prince was nominally under regency of his father, Norway received a level of independence and the administration continued under Vidkunsson.