Geryon was the son of Chrysaor and Callirrhoe. Chrysaor had sprung from the body of the Gorgon Medusa after Perseus beheaded her, and Callirrhoe was the daughter of two Titans, Oceanus and Tethys. With such distinguished lineage, it is no surprise that Geryon himself was quite unique. It seems that Geryon had three heads and three sets of legs all joined at the waist.
To accomplish his tenth labor, Hercules had to journey to the end of the world. Eurystheus ordered the hero to bring him the cattle of the monster Geryon.
Geryon lived on an island called Erythia, which was near the boundary of Europe and Libya. On this island, Geryon kept a herd of red cattle guarded by Cerberus's brother, Orthus, a two-headed hound, and the herdsman Eurytion. Hercules set off on for Erythia, encountering and promptly killing many wild beasts along the way to the place where Libya met Europe.
Sailing in a goblet, which the Sun gave him in admiration, Hercules reached the island of Erythia. Not long after he arrived, Orthus, the two-headed dog, attacked Hercules who promptly bashed him with his club. Eurytion followed, with the same result. Another herdsman in the area reported these events to Geryon. Just as Hercules was escaping with the cattle, Geryon attacked him. Hercules fought with him and eventually shot him dead with his poisonous arrows.