Gefjon was also one of the maidens in Frigga’s palace, and to her were entrusted all those who died unwedded, whom she received and made happy for ever.
According to some authorities, Gefjon did not remain a virgin herself, but married one of the giants, by whom she had four sons. This same tradition goes on to declare that Odin sent her before him to visit Gylfi, King of Sweden, and to beg for some land which she might call her own. The king, amused at her request, promised her as much land as she could plough around in one day and night. Gefjon, nothing daunted, changed her four sons into oxen, harnessed them to a plough, and began to cut a furrow so wide and deep that the king and his courtiers were amazed. But Gefjon continued her work without showing any signs of fatigue, and when she had ploughed all around a large piece of land forcibly wrenched it away, and made her oxen drag it down into the sea, where she made it fast and called it Seeland.
“Gefjon drew from Gylfi,
Rich in stored up treasure,
The land she joined to Denmark.
Four heads and eight eyes bearing,
While hot sweat trickled down them,
The oxen dragged the reft mass
That formed this winsome island.”
Norse Mythology (R. B. Anderson).