Eriphyle was born into the royal house of Argos, the daughter of King Talaus and his wife Lysimache. Her father belonged to a family thick with seers and heroes, descended through Bias and Melampus from the wider clan of Argive royalty. Her brothers included Adrastus, the future king who would gather armies against Thebes, and Parthenopaeus, one of the doomed champions of that expedition. Argos itself was one of the great cities of the Greek heroic age, a kingdom of bronze halls, chariots and oracle-speaking heroes. Eriphyle's place in that world was defined by two bonds: kinship with the royal family and marriage to one of Greece's most famous prophets.

Her husband was Amphiaraus, son of Oicles and a descendant of Melampus, the seer who had once healed the madness of the women of Argos. Amphiaraus could read the will of the gods in birds, entrails and thunder. During a feud in Argos, he killed Eriphyle's father Talaus, putting himself and her brother Adrastus on opposite sides. Time healed the quarrel. When peace returned, Adrastus offered Eriphyle to Amphiaraus in marriage, joining former enemies through a royal union. Eriphyle bore Alcmaeon and Amphilochus, with later traditions adding daughters such as Eurydice, Demonassa and Alcmene. The marriage joined prophecy to kingship, but it also rested upon a dangerous promise. Amphiaraus swore that if he and Adrastus ever disagreed again, Eriphyle would decide between them.

The object that would destroy the marriage had already passed through the cursed House of Cadmus. Harmonia, daughter of Ares and Aphrodite, had received the golden necklace and robe as gifts for her wedding to Cadmus, founder of Thebes. The necklace was said to have been made by Hephaestus, the lame god of the forge, who was angered by Aphrodite's adultery with Ares. Statius imagined its horror with baroque precision: emerald fire, adamant stamped with ill omens, Gorgon eyes, green serpent crests, the apples of the Hesperides, the golden fleece, poisons and the adder taken from Tisiphone's hair. Whether or not every detail belonged to the oldest tradition, the gift carried disaster. Harmonia and Cadmus suffered and were eventually transformed into serpents. Their daughter Semele died. Jocasta unwittingly married her own son Oedipus. When the truth of that marriage was revealed, Jocasta hanged herself and Oedipus tore out his eyes. The necklace then passed down the royal line to Polynices.

Trouble began when Eteocles, son of Oedipus, refused to surrender the throne of Thebes to his brother Polynices. The brothers had agreed to rule in alternate years, but Eteocles kept the kingship when his turn ended. Polynices fled to Argos, where a storm-driven night brought him and the exiled hero Tydeus to the palace of Adrastus. An oracle had told Adrastus to marry his daughters to a lion and a boar. When he saw the skins and fighting spirit of the two strangers, he recognised the signs and gave Argia to Polynices and Deipyle to Tydeus. Adrastus promised to help both sons-in-law recover their lost kingdoms, beginning with Polynices and Thebes. His army would gather seven champions and seven companies against the seven gates of Thebes. The war became known as the Seven against Thebes.

Eriphyle entered the war through her husband's resistance. Amphiaraus looked into the future and saw ruin. Zeus had flashed thunder and urged the Argives not to march, yet Adrastus and Polynices were determined to fight. Amphiaraus refused to join a campaign whose end he could already see: six of the champions would die and only Adrastus would return. The king could not compel him without breaking their old arrangement. The oath required the dispute to be decided by Eriphyle. Polynices therefore came to the queen, not to argue military strategy but to buy her judgement.

In the fullest Roman version, Polynices first appealed to his wife Argia, who understood how to reach Amphiaraus through his wife. Argia had seen the necklace in the treasure of Thebes and urged her husband to place it in Eriphyle's hands. The queen accepted. Homer gives the act its terrible summary: Eriphyle took precious gold as the price of the life of her own lord. Amphiaraus saw the gift. He knew that his wife had sold him, but the oath stood between him and refusal. Eriphyle ruled that the expedition should proceed and that her husband should march among the Seven.

The scene of departure became famous enough to be carved on the Chest of Cypselos at Olympia, the ornate cedar chest Pausanias saw centuries later. Eriphyle stands before the house wearing the necklace. Her daughters are beside her, and the naked boy Alcmaeon is present. Amphiaraus has already placed one foot upon the chariot, his sword drawn in such rage that he seems about to strike his wife. Baton, his charioteer, holds the horses. The prophet has seen death, received his sentence and obeyed the woman who betrayed him. Before the chariot rolls towards Thebes, he commands Alcmaeon and Amphilochus to remember what they have seen. When he is gone, they are to avenge him upon their mother.

The army marched to Nemea, where the infant Opheltes was killed by a serpent and the heroes founded funeral games in his honour. At Thebes, Amphiaraus fought despite his knowledge and resentment. The expedition failed as he had foreseen. Capaneus, who boasted that not even Zeus could stop him, was struck by a thunderbolt while scaling the walls. Polynices and Eteocles killed one another in single combat. Tydeus was mortally wounded and, in one brutal episode, ate the brains of his slayer. Amphiaraus fled from the battlefield as Periclymenus, the Theban hero, pursued him. Before the spear could strike him in the back, Zeus split the earth with his thunderbolt. The chasm opened, horses and chariot fell into the darkness, and Amphiaraus vanished beneath the plain. The earth closed above him. He became a chthonic hero and oracle rather than a corpse.

Eriphyle was left a widow in Argos, still holding the necklace. Her betrayal had destroyed the husband she had compelled to obey her. Yet the story was not finished. A generation later, the sons of the dead champions gathered as the Epigoni, the After-born, to attack Thebes again and recover the honour of their fathers. Alcmaeon, now grown, was chosen as leader, but he hesitated. Before he could lead an army, he had to settle the command left by Amphiaraus. The gods and the dead prophet demanded punishment for the woman whose gift had sent him to his doom.

The House of Cadmus offered her a second gift. Thersander, son of Polynices, possessed the robe of Harmonia and gave it to Eriphyle in return for persuading Alcmaeon to join the Epigoni. The robe, like the necklace, came from the wedding of Harmonia and Cadmus and carried the same doom. Eriphyle accepted. She urged her son to lead the second war, and Alcmaeon obeyed. This time the Argive descendants won. The Epigoni took Thebes and avenged the defeat of their fathers. Alcmaeon returned to Argos with victory behind him and his mother's double treachery laid bare.

Alcmaeon killed Eriphyle. Ancient tellings leave the weapon and final words unrecorded, but they make the reason clear: she had accepted the necklace that killed Amphiaraus and the robe that had nearly placed her son among the dead. The act fulfilled his father's command, yet it also made Alcmaeon a matricide. The Erinyes, the avenging goddesses of kindred blood, pursued him. Madness seized him, and wherever he went the memory of his mother followed. His dead mother became the accusation that he could not escape. An oracle of Apollo told him that he could find release only in a place that had not existed when he killed her.

Alcmaeon fled through Greece and came at last to the mouth of the river Achelous, where new land had formed from silt. The river god Achelous purified him, and Alcmaeon married the god's daughter Callirrhoe. Before that, however, he had stayed with King Phegeus, married his daughter and given her the necklace and robe of Harmonia as tokens. Callirrhoe learned of the treasures and demanded them for herself. Alcmaeon returned to Phegeus under a false story, hoping to recover the gifts, but the king discovered his intention and sent his sons to kill him. The murderous circuit continued around Eriphyle's necklace. Her two bribes had already killed her husband, her son, the king who sheltered him and the king's sons. Alcmaeon's own sons avenged their father, took back the treasures and dedicated the necklace to Athena at Delphi, hoping that the god's temple could contain what human greed could not.

The queen herself received a grim immortality. In the Odyssey, Odysseus descends to the Underworld and sees the shades of tragic women. Among them stands Eriphyle, still wearing the memory of the gift that destroyed her household. Homer calls her hateful and repeats the terrible equation: she took gold in exchange for her husband's life. Virgil gives the dead queen a more physical punishment. In the Aeneid she appears in the gloom of the Underworld, displaying the wounds inflicted by her son and unable to hide the price written on her body. Eriphyle has no heroic rescue, no apotheosis and no forgiveness. Her immortality is exposure.

The necklace itself survived in relic and story. Pausanias saw at Amathus in Cyprus a necklace said to have belonged originally to Harmonia and later called the Necklace of Eriphyle because it was the bribe that betrayed her husband. He doubted that the object before him, with its green stones and gold, matched Homer's simpler description of solid precious gold. The argument over its appearance belonged to a deeper dispute over whether the treasure was historical treasure, divine curse or literary invention. No physical necklace could contain the meaning the story gave it. Gold became the measure of a life, a marriage, an oath and a kingdom.

Eriphyle's story endured in art, epic and tragedy long after the heroic age vanished. Greek vase painters showed Polynices offering the necklace while the doomed Amphiaraus looked on. The Chest of Cypselos froze the departure scene: the wife with the treasure, the husband with the drawn sword, the children witnessing the beginning of their own curse. Statius gave the necklace the most elaborate horror in ancient literature, while later dramatists and opera composers returned to the clash between obedience, greed, prophecy and family loyalty. Every retelling leaves the same question suspended. Amphiaraus was bound by oath, but Eriphyle was bound by nothing except her own choice. She saw the omens, understood her husband's gift and still accepted the gold. Her punishment did not erase the choice. It made the choice unforgettable.