Sleipnir Picture

Early on when Asgard was just being built, a stonemason offered to construct a wall for the gods, asking for the sun, the moon, and the goddess Freya in return. Loki convinced the gods to agree, though only if the stonemason could do the impossible and build it with three seasons and without any man's help.
The stonemason brought in his stallion Svadilfari and was finishing the wall three days before the deadline. The gods, not wanting to lose the deal, blamed Loki for the mess and charged him with fixing it. Loki changed himself into a mare and "distracted" Svadilfari, preventing the stonemason from finishing. The stonemason then tried taking Freya by force, but was promptly killed by Thor.

Some time later Loki gave birth to Sleipnir, who grew up to be the greatest of all horses and Odin's personal steed.
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