- For other uses of the name Diomedes, see Diomedes (disambiguation).
Diomedes was a barbaric king of the Bistonian tribe of Thrace who fed his horses a diet of human flesh.
Hercules was commanded to fetch Diomedes' flesh-eating horses by King Eurystheus as the eighth of his twelve Labors. He captured the animals and left them in the care of his young squire Abderos, while he went to deal with Diomedes. During his absence, the boy was devoured. Hercules then fed Diomedes to the beasts, stilling their unnatural appetite with a meal of their master's flesh.