Sleipnir

The builder laid stone after stone around the gods’ town. He had offered to build a strong burg that would keep out mountain giants and frost giants, even if they entered Midgard. In return, he demanded Freyja, the sun, and the moon. The gods agreed on one condition: he had to finish the burg in one winter. If any part remained unfinished on the first day of summer, the bargain would be void.

The builder’s stallion, Svaðilfari, dragged huge boulders to the wall. The work advanced so quickly that the gods feared the builder would succeed. They asked Loki to stop him. At dusk, as the builder led Svaðilfari towards the quarry, Loki changed into a mare and appeared beside the path. The mare drew the stallion into the woods. Svaðilfari broke free from his harness and followed, while the builder shouted after him. Without the stallion, the builder could not bring the stones quickly enough. The burg remained unfinished when summer began, so the agreement was void.

The builder then revealed himself as a giant and grew furious. The gods called on Thor. Thor returned, recognised the builder as a giant, and struck him with Mjolnir. The blow broke the giant’s skull and sent him down to Niflhel. The builder therefore received neither Freyja nor the sun or moon.

Loki later gave birth to a foal after his time with Svaðilfari. The foal was grey and had eight legs. It grew into Sleipnir, a powerful horse that could outrun the wind. Loki gave Sleipnir to Odin, who claimed him as the finest horse among gods and men.