When Hephaestus found out that his wife Aphrodite, goddess of love, had an affair with Ares, god of war, he became enraged and developed a scheme with which he managed to ridicule both of them to the rest of the Olympian gods. He also said that any child that would be produced by this union would be cursed. Aphrodite had a daughter, whom she named Harmonia. This daughter later became the wife of the legendary founder of the city of Thebes, Cadmus. As soon as Hephaestus found out about the marriage, he went to Harmonia and offered her the necklace as a gift. He had previously cursed the necklace to bring misfortune to anyone who wore or possessed it; at the same time, though, the necklace was able to bring eternal youth and beauty to its bearer. According to the myths, the necklace was made of gold and jewels, and had the shape of two serpents forming a clasp with their open mouths.
Harmonia and her husband were eventually turned into serpents, and the necklace was inherited by their daughter, Semele. It also brought her demise, as the day she wore it, she was visited by a disguised Hera and was tricked into asking her lover, who was Zeus in disguise, to reveal himself; Zeus was forced to comply causing her instant death. The necklace later fell into the hands of Queen Jocasta, who remained young and beautiful thanks to it. She unknowingly married her son Oedipus, and when the truth was revealed, she killed herself, while Oedipus tore his eyes out. Polynices inherited the necklace and gifted it to Eriphyle, eventually leading to her demise as well. It then went into Arsinoe's hands, before finally reaching the hands of Amphoterus and Acarnan. They both decided to offer the necklace to the Temple of Athena in Delphi, in order to stop any further misfortunes. The necklace was stolen, however, by the tyrant Phayllus, who offered it to his lover; however, her son fell into madness, set fire to the house, killing everyone in there. This is the last story linked to the Necklace of Harmonia.