The Necklace of Harmonia was born in jealousy and fire. Hephaestus, the son of Hera, the queen of Olympus, and the greatest craftsman the cosmos had ever known, had been married to Aphrodite, the goddess of love and beauty, in a union arranged by Zeus, the king of the gods. But Aphrodite did not love the lame smith. She loved Ares, the Olympian god of war, a deity whom the other gods despised for his love of bloodshed, and their secret affair was the scandal of Olympus until Hephaestus trapped them in a net of golden threads and exposed them to the laughter of the gods. Humiliated and enraged, Hephaestus turned his craft to vengeance. He forged a necklace of gold and set it with stones of such enchanted beauty that any woman who saw it would desire it above her own life, and into its clasp he wove a curse: whoever wore it would suffer a fate of violence, betrayal, and untimely death.

The occasion for the gift was the wedding of Cadmus and Harmonia. Cadmus was the Phoenician prince who had founded the city of Thebes by sowing the teeth of the Dragon of Ares, the sacred serpent he had slain at the spring of Ares, and from those teeth had sprung the Spartoi, the Sown Men who became the ancestors of the Theban nobility. Harmonia was the daughter of Ares and Aphrodite, the very product of the adulterous union that had enraged Hephaestus, and the gods themselves attended her wedding. Hephaestus presented the necklace to the bride as a wedding gift, and Harmonia, dazzled by its beauty, fastened it around her throat. The curse was set in motion.

Harmonia bore Cadmus five children, and every one of them was touched by disaster. Their son Polydorus became king of Thebes but died young. Their daughter Semele was consumed by the thunderbolt of Zeus when she insisted on seeing his true divine form. Their daughter Ino went mad and leaped into the sea with her son Melicertes in her arms. Their daughter Agave tore her own son Pentheus apart in a Dionysiac frenzy. And their son Illyrius wandered the earth in exile. Cadmus and Harmonia themselves were eventually transformed into serpents and driven from Thebes, and Harmonia died wearing the necklace that had doomed her house. But the jewel did not die with her. It passed to her daughter Semele, and from Semele it passed through the women of Thebes like a fever, each wearer falling to a more terrible end than the last.

The necklace appears again in the hands of Jocasta, the queen of Thebes who would become the mother and wife of Oedipus. Some say she received it as a wedding gift when she married Laius, the king of Thebes, and that it was already in the treasury of the city, passed down from Harmonia through the generations. Others say it came to her through a different line of descent. Whatever its path, the curse held true. Jocasta's husband Laius was murdered by their own son Oedipus, who did not know him, and Jocasta herself, upon discovering that she had married her son and borne his children, hanged herself in the palace bedchamber. The necklace, if she wore it at the end, had done its work: the house of Thebes was destroyed by the very incest and parricide that the curse had promised.

But the necklace's most famous bearer was Eriphyle, the wife of Amphiaraus, the great seer of Argos. Amphiaraus was one of the Seven Against Thebes, the seven Argive champions who marched to restore the exiled Polynices to the throne of Thebes, and he knew through his prophetic gift that the expedition would end in his own death. He tried to hide from the call to war, but Polynices bribed Eriphyle with the Necklace of Harmonia, which he had obtained from his wife, the daughter of the Theban king. Eriphyle, dazzled by the jewel's beauty, betrayed her husband's hiding place, and Amphiaraus was forced to march. He charged her with a terrible oath before he left: their son Alcmaeon must avenge his father's death by killing his own mother. The Seven were defeated at Thebes, Amphiaraus was swallowed alive by the earth, and Eriphyle kept the necklace, wearing it with pride while her husband rotted in the ground.

Years later, Alcmaeon fulfilled his father's command. He confronted Eriphyle, accused her of treason and greed, and struck her down with his own hand. He took the necklace from her corpse and fled, pursued by the Furies, the Erinyes, the goddesses of vengeance who pursue oath-breakers and kin-slayers to the ends of the world. Driven mad by their torment, Alcmaeon wandered Greece until he came to the city of Psophis in Arcadia, where King Phegeus purified him of his mother's blood and gave him his daughter Alphesiboea in marriage. But the curse was not finished. Alcmaeon gave the necklace to his new wife as a wedding gift, and soon the people of Psophis turned against him, remembering that he was a matricide. He fled again, this time to the mouth of the River Achelous, where he married the river-god's daughter Callirhoe and had two sons. Callirhoe learned of the necklace and demanded it, believing that its beauty would make her the most glorious woman in Greece. Alcmaeon returned to Psophis to retrieve it from Alphesiboea, but Phegeus, enraged at the betrayal of his daughter, had Alcmaeon ambushed and killed. The king's sons took the necklace back to their sister, but she too was cursed, and the chain of death continued.

At last the necklace was dedicated at Delphi, the oracle of Apollo, in the hope that the god's sanctuary could break the curse. But even there it brought trouble. The Phocian general Phayllus stole it to bribe his wife, and she wore it and died. The necklace passed to Agapenor, the king of Arcadia who led his men to Troy, and from him into obscurity. Some say it was finally destroyed, its gold melted down and its stones scattered. Others say it still exists somewhere, waiting for the next woman vain enough to fasten it around her throat.