In Norse mythology, the god Rig was travelling and happened upon a farm owned by Ai ("great grandfather") and his wife, Edda. They offered Rig shelter and a low quality meal. He slept between the pair at night; Edda gave birth nine months later to a son whom they named Thrall. Thrall grew up strong and ugly. He married Thir and had twelve sons and nine daughters. They became the serfs of Norse society.
