According to the chronicler Saxo Grammaticus, Magnus was recognized by the Geats (Götarna) of Gothenland, but according to the Westrogothic law, the prerogatives of selecting a king lay with the Svear, another tribe to the north of the Geats.
Menurut penulis sejarah Saxo Grammaticus, Magnus diakui oleh Geats (Götarna) Gothenland, namun menurut Hukum Westrogothic, hak prerogatif memilih seorang raja awam dengan Svear, suku lain di utara Geats.