In the Age of the Vikings, Odin was pictured traveling through the air on Sleipnir, his mighty horse with eight legs, which would carry him to the land of the dead to his realm.
The story of the birth of this horse of Odin is found in the account of the building of the wall around Asgard, the stronghold of the gods. A giant offered to build the wall for them in the space of one winter. It was agreed that, if he could finish the work within the stipulated time, he should have the goddess Freya and the Sun and Moon as payment.
The gods thought themselves quite safe in making such a bargain, but the giant brought with him a marvelous horse, called Svadilfari, which was so intelligent and swift that when the beginning of Spring was only three days away, the wall was practically complete.
The gods, however, were saved from making payment by the cunning of Loki, the trickster of Asgard. He took on the form of a mare and neighed at the stallion until he was lured away from his work. As a result, the wall was never finished, and Thor slew the giant with his hammer.
After the meeting of the stallion and the mare, Loki gave birth to the eight-legged colt. "This" was Sleipnir, the finest of all steeds, whom Odin kept for his own.
The wonderful horse Grani, given by Odin to Sigurd the Volsung, was said to be bred from Sleipnir and be one of the best horses of men.
Odin once carried the hero Hadding off on his horse, covering him with his blue mantle. They traveled over land and sea, and visited the Hall of Odin, where Hadding drank from Odin's mead. Clearly Sleipnir could carry the living to the realm of the dead.
Brightest of Blessings,