The Mares of Diomedes – Eighth Labor of Heracles

The Mares of Diomedes were four horses that used to eat human flesh. They were owned by king Diomedes of Thrace, who kept them tethered with chains in one of his cities. The local populace was afraid of the Mares for many years until the great demigod hero, Heracles, came to their lands and took away the horses, thus relieving the Thracians of their terror.

Key Facts

NamesDeinos, Lampon, Podargos, and Xanthos
Ancient Greekἵπποι Διομήδεος (Δήμος, Λάμπων, Πόδαργος, και Ξάνθος)

Origins of the Mares of Diomedes

Mares of Diomedes
Metropolitan Museum of Art, CC0, via Wikimedia Commons

In the old texts, there is no mention of the Mares’ origins. The legend has king Diomedes owning the horses, but not how he got possession of them. The local residents of Thrace viewed the Mares as a threat mostly because they ate humans. However, one day the demigod son of Zeus, Heracles came and according to one of his labors, he snatched away the Mares of Diomedes.

Meaning of their names

The names of the Mares of Diomedes were the terrible (Deinos), the shining (Lampon), the swift (Podargos), and the yellow (Xanthos).  

The myth of the Mares of Diomedes

Diomedes was the son of Ares (the god of war) and Cyrene (a mortal princess). He was the king of a region called Thrace, and his palace was on the shores of the Black Sea. Diomedes was not a benign ruler, his people hated and feared him for his unfair taxes and tyrannical laws. Those who openly opposed him were sent to the town of Tirida where they were consumed – alive in most cases – by a herd of large feral horses known as the Mares of Diomedes. The Mares are among the best known ancient Greek monsters.

The horses were four in number, all female, and they were as beautiful as they were wild. An unknown madness has fallen on them since they were born and they could only eat human flesh. It may be suggested that Ares gave these horses to his son, Diomedes, as a gift for his rule of Thrace, but that cannot be attested anywhere.

The beasts

The Mares of Diomedes were truly magnificent animals. But their inherent madness made them a living nightmare to anyone who saw them. Only when the horses ate human meat did the condition appease.

They were always bound with iron chains to a bronze manger in the Thracian town of Tirida. Men of Diomedes would look to the horses’ needs putting some poor fellow, a stranger most likely, in that manger thus feeding those terrifying beasts and keeping them under temporary control.

The hero

Heracles before capturing the Mares of Diomedes
Luis García, CC BY-SA 3.0, via Wikimedia Commons

One of Heracles’ twelve labors was to go to Thrace and steal the Mares of Diomedes. He was to bring these beasts to king Eurystheus of Tiryns to prove his worth. At first, the demigod hero, accompanied by a few men, traveled to Tirida where he fought and defeated Diomedes’ soldiers who were watching over the horses. Heracles then broke the chains holding the mares to the manger and took them down the coast.

Diomedes, alarmed by the theft, sent a unit of his best men to stop the thieves. Leaving the horses to his good friend Abderus, Heracles turned to face Diomedes and his small army. Heracles won the battle and managed to capture Diomedes alive. But, when he returned to Abderus he found out that the Mares had eaten his friend. Filled with sorrow and anger, Heracles avenged Abderus’ death by feeding Diomedes to his mad horses.

After this, Heracles was said to have founded a city named Abdera to honor the memory of his fallen companion. The Mares were taken to king Eurystheus, who set them free. These feral animals roamed around Tiryns for a while before they were eaten by wild beasts.

Various versions

There are some other versions of how Heracles stole the Mares of Diomedes. One of them speaks of the demigod escaping an assassination plot by Diomedes. Heracles released the horses in the dead of night and then attacked Diomedes and his men, killing them all except the king, who was ultimately fed to his own horses.

In another version, Heracles first fed Diomedes to his Mares and then released them. The ending also varies. One version speaks of the Mares turning permanently calm if they were allowed to roam the fields of Argos. In another version, king Eurystheus sent them to Mount Olympus as a sacrificial gift to Zeus. The King of the gods the sacrifice however and sent wild beasts to devour the mares.

Depictions of the Mares of Diomedes

Mares of Diomedes
Metropolitan Museum of Art, CC0, via Wikimedia Commons

The Mares of Diomedes were four, tall, almost gigantic, white horses. Their mane was either brown or yellow, and they feed exclusively on human flesh. In some of the old stories, the Mares were breathing fire. However, Heracles was protected because of the Nemean Lion, The Indomitable Beast pelt he was wearing.

In the old texts


Euripides mentions the Mares of Diomedes in two of his plays – Heracles and Alcestis, The Woman Of Sacrifice.

‘He (Heracles) rode out in a four-horse chariot,
and with an iron bit he tamed
the horses of Diomedes, who ate
in their own blood-stained stalls,
their gory jaws devouring with joy
the flesh of human beings, to sate
voracious man-eating appetites.’

Euripides’ Heracles

Diodorus Siculus writes about the Mares of Diomedes in his work Bibliotheca Historica.

‘The next Labour which Heracles undertook was the bringing back of the horses of Diomedes, the Thracian. The feeding-troughs of these horses were of brass because the steeds were so savage, and they were fastened by iron chains because of their strength, and the food they ate was not the natural produce of the soil but they tore apart the limbs of strangers and so got their food from the ill lot of hapless men.’

Diodorus Siculus’ Bibliotheca Historica 4.15.3


Ovid, Lucan, Seneca and Statius talk about the Mares of Diomedes in their works as well.

‘Don’t you recall the memory of cruel Diomedes,
That savage who fed his horses with human flesh?’

Ovid’s The Heroides ‘Deianira to Hercules’


How many were the Mares of Diomedes?

The Mares of Diomedes were four horses. Deinos, Lampon, Podargos, and Xanthos were their names and they ate only human meat as an unknown madness was forcing them to this unusual diet.

Who gave birth to the Mares of Diomedes?

No one cites or even hints at the parents of these untamed horses. A theory suggests that they were once normal horses that Ares, the god of war, cursed for unknown reasons (or perhaps to make them more ferocious and battle strong) and then gave them as a present to his son, Diomedes.

Featured Image Credit: Antonio Tempesta, CC0, via Wikimedia Commons

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Vasilis Megas

Vasilis Megas (a.k.a. Vasil Meg) was born in Athens, Greece where he still resides writing epic fantasy and sci-fi books. He is a Greek - and Norse Mythology enthusiast, and he is currently working as a creative/content writer, journalist, photographer and translator.