Geryon owned the cattle Hercules stole in the Tenth Labor.
Geryon was a monstrous figure commonly described as having three bodies or three joined forms. He lived in the far western region of the known world, traditionally associated with the island of Erytheia. His red cattle were guarded by the herdsman Eurytion and the two-headed dog Orthrus.
Hercules traveled west to obtain the herd. During the journey, he set up the Pillars of Hercules at the entrance to the Mediterranean in later tradition. He killed Orthrus, Eurytion, and finally Geryon, then drove the cattle back toward Eurystheus.
The cattle’s color and Geryon’s threefold body distinguish this labor from the later quest for the golden apples. Greek geographical ideas about the far west changed over time, so ancient authors placed Erytheia in different locations. The central mythic feature remains Geryon’s extraordinary body and his prized herd.