To the northeast of Hellas, on the eastern side of Macedonia, lies the region of Thrace. Today, this area is made up from regions of three countries: Hellas (Greece), Bulgaria, and Turkey. About half of Thrace is in Bulgaria, while the other half is split between Hellas and Turkey. Thrace was bordered to the east by the Euxine (Black) Sea, the Sea of Marmara to the southeast, and the Aegean to the south. The Turkish island of Gökçeada, also called Imbros, Greek island of Σαμοθρᾴκη (Samothrace) were also part of ancient Thrace.
All Thracians were said to have descended from Θρᾷξ (Thrax), who himself was a son of Ἄρης (Ares), god of war: untamed and violent. So associated were Thrace and Ares that the god’s gilded shield was kept in the temple of Ares at Bistonia on the shores of Lake Bistonis in the south central part of Thrace.
The Thracian tribe living around the lake were called the Bistones, who descended from Biston, another son of Ares, who built the city there at a time shrouded in the mists of legend.
In fact, all the most ancient Thracian kings claimed Ares’ patronage. It is with another Bistone king, Diomedes, that our story with Herakles takes shape.
After delivering the Cretan Bull, Eurystheus ordered our hero to Lake Bistonia. Herakles was to go to Bistonia, seek and audience with King Diomedes, and entreat to bring Diomedes’ mares back to Mycenae.
Diomedes, like all Thracian kings, was a man of violence and passion. The thrill of ending the lives of others was his delight. He was addicted to bringing death. Diomedes was a death-bringer. It was his addiction.
Like all addicts, he sought to find ways to lengthen the ecstasy of his high. He found his fix in training four mares to desire and devour human flesh.
The mares Podargos (“the swift-footed”), Lampon (“the shining”), Xanthos (“the blonde”), and Deinos (“the terrible”), were all chained to a bronze manger because they were so wild from eating nothing but human flesh for as long as they could remember.
Diomedes fed his greatest enemies to these special four mares: those special enemies he wished to endure suffering of the highest magnitude. Diomedes dismembered them, disemboweled them, and cut open their skulls while they were yet alive so that the mares could feast first upon his victims’ limbs and bowels before finishing them off by supping their brains.
Diomedes always wore a golden chain with a locket around his neck. Inside the locket was a feather from Ares helmet dipped in the blood of all four mares. The blood, the feather, locket and chain were enchanted so that Diomedes always knew where his mares were and when they were at their most ravenous.
It was late in the day when Herakles crossed over the hill on the far side of Lake Bistonia. Across its still waters was a steep, hilly peninsula that jutted out into the Euxine Sea [not far from Byzantium (modern day Istanbul)]. As Herakles surveyed the landscape, his eye caught an unusual, black shape in the distance. His hero’s sixth sense tingled, and he knew that he would find the mares there in the blackness.
As he approached, he noticed also a small cave just beyond the mares and the lake with a small path leading toward the peninsula. He had an idea.
As it was nearing the end of day, the four mares were settling down a bit. Perhaps they had also recently eaten, for when Herakles neared them, he was surprised to find them relatively calm.
He walked up to them, picked up the bronze manger, and began to lead them toward the cave. Herakles was beginning to think that this task was going to be almost too easy, but, then, he knew nothing of the chain around Diomedes’ neck and its connection to the night-mares.
When Herakles touched the bronze manger, picking it up, a shock went through Diomedes’ body like a bolt of lightning. The enchantment on his locket allowed him to see, with his mind’s eye, what his mares were seeing. He saw Herakles! Instantly, the shock turned to blood-red rage, and Diomedes grabbed his sword and flew from his palace without a second thought. Oh, what a terrible death he imagined for Herakles!
Night fell on the Thracian countryside.
Perhaps it was divine intervention, or perhaps not, but as Diomedes crossed into the fields, Herakles knew he was coming. The mares became restless. Fire blazed in their eyes, and they began to thrash wildly and gnash their teeth.
With one great thrust, Herakles made for the now-close cave, and, leaving the mares and their manger outside, he ran into the cave and waited for Diomedes.
All night, Herakles remained vigilant. The wailing and unearhtly neighing of the four night-mares was deafening. As Diomedes came into view, Herakles summoned all his strength and ran out of the cave, grabbing the manger and dragging the mares up the hill onto the peninsula.
Leaving the mares at its tip, near the water, Herakles dug a trench with his axe forming an island that isolated the mares. He now could face Diomedes in battle.
The two men clashed for what seemed an eternity. A fantastic battle it was! Just as it looked as if Herakles would be overcome, the mares, in their excitement, neighed and let out an enormous plume of flame on their breath. As Diomedes looked back upon them to admire his unholy handiwork, Herakles slipped from his grasp, and, with one swift and powerful stroke of his axe, chopped off Diomedes’ head.
As Diomedes’ head rolled toward the water, Herakles struggled to his feet, grabbed the head, and threw it to the mares. He fed the rest of Diomedes’ body to them, and they became tame.
Herakles broke the chain binding them to the bronze manger, and with it and the chain from Diomedes’ neck, Herakles bound their mouths and drove them all the way back to Mycenae and Eurystheus.
Eurystheus, annoyed and amazed yet again by Herakles’ victory, sent him out again to retrieve the belt of Hippolyte, queen of the Amazons.