スノッリ・ストゥルルソン
It was written in "c." 1225 by Snorri Sturluson, who made use of the saga by the priest Styrmir Kárason, now largely lost except for some fragments in "Flateyjarbók". A revised version of the Separate Saga was later incorporated into the "Heimskringla" ("c." 1230), often ascribed to Snorri Sturluson.