Heimskringla thumb|upright|Freya (1901) by Anders Zorn The Heimskringla book Ynglinga saga provides a euhemerized account of the origin of the gods, including Freyja. In chapter 4, Freyja is introduced as a member of the Vanir, the sister of Freyr, and the daughter of Njörðr and his sister (whose name is not provided). After the Æsir–Vanir War ends in a stalemate, Odin appoints Freyr and Njörðr as priests over sacrifices. Freyja becomes the priestess of sacrificial offerings and it was she who introduced the practice of seiðr to the Æsir, previously only practiced by the Vanir.
hEiMSKRiNgLa thumb|uPright|freya (1901) BY andeRs zorn tHe hEimsKRIngla BoOk yngLinga sAGa pRoVides a EuHeMeriZed AcCount of tHe ORigiN of the gOds, InCLUDiNG fReyja. In ChapteR 4, fReYjA iS intrOdUCed as A meMBEr of the vANiR, the siStEr OF freyR, and the daUgHTer oF NjöRðr and His SIsteR (WhosE Name is nOt proVidEd). AfTer The Æsir–vAnir war ends in a STaLematE, odin aPpOInTs Freyr and njöRðr aS prIEsTS oveR sacRificES. frEyjA BecomEs tHE PRiestess oF SacriFiCIAl oFfErInGs anD iT was sHe who InTRoduCeD the praCtIce oF seIðR tO THE æsIr, PReVioUslY onLy PractIced by the vanIR.