In Norse mythology, Vifinn was the father of Hjúki and Bil, a brother and sister (respectively) who according to Gylfaginning were taken up from the earth by the moon as they were fetching water from the well called Byrgir, bearing on their shoulders the cask called Saegr and the pole called Simul. They now follow him on his nocturnal journey, "as may be seen from the earth". Later in Gylfaginning, Snorri reckons Bil among the Ásynjur along with Sól. The moon is personified as Mani.