Depending on the culture, white horses symbolize purity, heroism or death. White is the rarest color of horse, and white horses have been associated with nobility in chivalry, with the sun in Greek mythology and with the end of the world in Christianity. They are often psychopomps, guides between the worlds of the living and of the dead.
As far back as Paleolithic times, the white horse has been a symbol of a connection between the everyday world and the afterlife or the land of the gods. The chalk Uffington White Horse, cut into the turf on a hillside in Oxfordshire, may be this sort of figure, and Epona, the Celtic horse goddess, rode a white mare to escort souls to the land of the dead and to bring dreams. The Valkyrie of the Norse rode white winged horses to collect the spirits of the heroes fallen in battle.
The white horse is the traditional steed of a good god or hero, and it is the only creature pure enough to bear the hero to triumph over evil. Sleipnir, Odin's eight-legged horse, was described as gray and most likely had a white coat but black skin. The white winged horse Pegasus bore the hero Bellerophon into battle and later carried Zeus' lightning bolts.
As befits its other role as psychopomp, a pale horse also bears the figure of Death in the Biblical Four Horsemen of the Apocalypse. In the Hindu religion, Vishnu's last avatar Kalki will also ride a white horse and usher in the end of the world.