Geryon's family began in blood. His father Chrysaor sprang from the neck of Medusa, the Gorgon whose face turned those who looked at her to stone, after the hero Perseus cut off her head. Medusa had conceived by Poseidon, and from the same wound came the immortal winged horse Pegasus. Chrysaor carried a golden sword, from which his name was made. Beyond Oceanus he married Callirrhoe, one of the three thousand daughters of Oceanus and Tethys, whose waters fed every spring and river. Their child was Geryon, the triple-formed ruler whose unusual body marked him as a monster, a wonder and a threat.

No two poets gave Geryon the same shape. Hesiod calls him three-headed Geryon, the strongest of all mortal men. Later vase painters and mythographers gave him the bodies of three men joined into one at the belly, each with a head, chest and arms, and splitting apart again into separate hips and legs. Some made him winged, with four wings rising from his backs. In battle he wore three helmets, carried three shields and thrust with three spears, presenting three fronts to a single attacker. The multiplication of limbs made him a small army in one body, but it also concentrated his fate. When Heracles found the vulnerable point, death could enter all his parts at once.

Geryon lived on Erytheia, the Sunset Isle, a land beyond the familiar Mediterranean and close to Oceanus, the river imagined to flow around the edges of the world. The island's name meant Red or Rosy, and ancient writers moved it over the map as geographical knowledge expanded. It was placed near Tartessos and Gades on the Iberian coast, among the islands beyond Gibraltar, or in the open sea beside the path of the setting sun. Its fields held something more valuable than silver: a herd of cattle whose hides were crimson because the sun's light stained them at evening. Their lowing, shambling mass made the cattle of the Underworld king Hades look ordinary by comparison.

The herd had two guardians. Eurytion, a giant herdsman born on the island, watched over the cattle and fought beside his master. Orthrus, the two-headed hound of the West, had been born to the monstrous pair Typhon and Echidna. He was the brother of Cerberus, the three-headed dog of Hades, and the mate of the Chimera, mother of the Sphinx and Nemean Lion. His two heads doubled his senses and doubled his fury. He could smell a stranger from the shore and attack with twice the teeth of an ordinary watchdog. Around the island swam and grazed the cattle of Hades, guarded by Menoetes, so Erytheia was a western frontier where herds belonging to gods and monsters grazed beneath the same evening sky.

Eurystheus, king of Mycenae and Tiryns, ordered Heracles to bring back Geryon's cattle as his tenth labour. By then Heracles had killed the Nemean Lion, the Hydra and the Erymanthian Boar, captured the Cretan Bull, tamed Diomedes' mares and taken Hippolyta's girdle. The cattle task was different. No monster guarded a treasure close to Greece. Geryon stood beyond the Pillars of Heracles at the boundary of the known world, and the hero had to cross continents, seas and deserts to reach him.

Heracles travelled west through Libya, where the heat of Helios, god of the sun, infuriated him. In one of the most audacious gestures in the labour cycle, he raised his bow and shot arrows at the sun itself. Helios was astonished by his courage and admired the hero's daring. Instead of burning him, the sun god gave Heracles a golden cup or goblet, the vessel in which Helios sailed each night from the western ocean back to the east. Heracles placed the cattle, provisions and himself in the shining cup and crossed the stream of Oceanus to Erytheia. Later tellers replaced the cup with a golden cauldron from an old epic tradition, but the image remained the same: the hero crossed the edge of the world in a vessel made for a god.

When Heracles landed, Orthrus caught his scent and rushed at him. One swing of the hero's olive-wood club ended the two-headed guard dog. Eurytion ran to help and met the same club. Menoetes, who was tending Hades' cattle nearby, rushed away to warn Geryon. Heracles rounded the red herd and began driving it towards the shore.

Stesichorus made Geryon's response a moment of human tragedy. His mother Callirrhoe came to him with open robes and begged her son to think of the parents who had raised him. Menoetes urged him to protect his cattle, his children and his race, but the fragments show that the three-bodied king already understood the danger before him. If he was immortal by birth and destined for Olympus, he could endure the shame of allowing his herd to be driven away. Yet if he was mortal, then death and old age could not be avoided. Better to meet his fate defending what was his than to live in disgrace. He chose honour and war.

Before the battle, the gods held council. Athena warned Poseidon, Geryon's grandfather on his mother's side and his protector by kinship, that she would stand beside Heracles and that the giant should not be saved. The Olympians had already marked the path of the labour. Geryon, born into a family of monsters and wonders, stepped forward in full armour: three crested helmets, three shields and three spears. He advanced like Ares, god of war, gathering his strength for a single combat against the strongest mortal hero.

Heracles chose stealth over glory. A Hydra's venom, taken from the Lernaean monster and preserved on his arrows, could kill gods and giants alike. He waited, struck Geryon with a stone or drove away the shield covering one face, then fitted a poisoned shaft to his bow. The arrow pierced the exposed brow, cut through flesh and bone, and passed straight through to the crown of Geryon's head. The venom spread through his three bodies. Geryon bent his neck to one side like a poppy whose petals suddenly fall, and the strongest of mortals died over his cattle.

The killing did not end the labour. Heracles had to take the herd home through dangers greater than the guardians of Erytheia. At the strait of Gibraltar he raised the two pillars of Heracles, Calpe and Abyla, to mark the boundary of Europe and Africa and the edge of his journey. Roman tradition carried the cattle to Italy. On the Aventine Hill, where Rome would one day stand, the fire-breathing monster Cacus stole four bulls and four heifers while Heracles slept. To confuse the trail, Cacus dragged the cattle backwards into his cave, repeating the trick once used by the infant Hermes when he stole Apollo's herd. The remaining cattle lowed to their stolen companions, revealing the theft. Heracles forced open the cave, strangled or bludgeoned Cacus and recovered the animals. King Evander of Pallanteum later honoured the victory and pointed to the very altar where Rome's cattle market, the Forum Boarium, would stand.

Hera, the relentless enemy of Heracles, still tried to make the return fail. She sent a gadfly to sting the cattle, scattering them across Thrace as the herd swam and fled in panic. She raised the River Strymon so high that it could not be crossed. Heracles gathered stones from the banks and built a rough causeway through the flood, leaving the river permanently blocked in that place. Even after recovering the scattered herd, he could not account for every animal. Some were lost in the wild, and the full crimson herd never reached Tiryns. Heracles eventually presented the cattle to Eurystheus, who sacrificed them to Hera. The queen of the gods gained the offering she had tried to prevent.

Geryon did not vanish entirely from the earth. Philostratus records a tomb at Gades, the city now called Cadiz, where two strange trees grew from the mound and blood dripped from their bark as gold once dripped from the poplars that wept over Phaethon. Aelian reports that the fatted bulls of Chaonia and Thesprotia in Epirus traced their ancestry to Geryon's herd. Pausanias makes Erytheia, daughter of Geryon by Hermes, the mother of Norax, founder of the first city of Sardinia. Later rationalising historians turned the triple-bodied monster into three warrior sons of the wealthy Iberian king Chrysaor, each commanding forces in his own region. Heracles invaded with an army, defeated the three brothers in succession and drove away their cattle. The three men acting as one became one three-bodied giant.

Ancient art kept returning to the death scene. Black-figure vases show Heracles shooting from the edge of the field while Orthrus lies dead, Eurytion falls and Geryon advances in three overlapping bodies. The Chest of Cypselos at Olympia carried an image of three men joined together beneath the blows of the club. Sculptures, mosaics and Roman reliefs contrast the single hero with the multiplied monster. The motif naturally expressed the labour's challenge: one man against a body that seemed to be three armies in one.

Roman epic made the journey part of Rome's own origin. In Virgil's Aeneid, Evander shows Aeneas the Forum Boarium and the Ara Maxima, the Great Altar, while recalling how Hercules arrived with Geryon's cattle and punished Cacus for the theft. The Greek labour was no longer a distant myth but a Roman landmark. Every merchant selling cattle in the Forum walked over ground where the western giant's red herd had once stood. Dante later borrowed Geryon's name for the winged monster of Fraud who carries Virgil and Dante from the seventh circle of Hell to the eighth, but this Geryon has no cattle and no three bodies. The medieval poet made the western monster into a symbol of deception.

The modern imagination has reclaimed the human side that Stesichorus gave him. Anne Carson's Autobiography of Red recreates the lost Geryoneis as a red, winged boy with a dog, a mother and a doomed love for Heracles. In that version, the triple-bodied monster becomes a lonely artist whose strange body is only another form of otherness. The transformation works because the ancient fragments already contain it. Geryon was a monster who debated immortality, a son who heard his mother's plea, a guardian who chose honour over safety and a king whose cattle were everything he had. Heracles had to cross the sun's path, kill a two-headed hound, defeat a triple-bodied warrior and fight his way home through Hera's traps. The giant lost because the gods had chosen the hero's path. He also lost because he refused to surrender without proving what kind of being he was.