Óthin appointed Njorth and Frey to be priests for the sacrificial offerings, and they were díar [gods] among the Æsir. Freya was the daughter of Njorth. She was the priestess at the sacrifices. It was she who first taught the Æsir magic such as was practiced among the Vanir. While Njorth lived with the Vanir he had his sister as wife, because that was the custom among them. Their children were Frey and Freya. But among the Æsir it was forbidden to marry so near a kin.
Ynglings Saga chapter 10
Freya kept up the sacrifices for she was the only one among the godheads who survived.
Therefore she became most famous, so that all women of rank came to be called by
her name. They are now called frúvur [ladies]. Thus everyone who is
mistress over her own property is called freya, and húsfreya
["lady of the house"] one who owns an estate.
