Harmonia necklace, in Greek mythology, was the necklace given as a gift to Harmonia, daughter of Ares and Aphrodite, on the occasion of her marriage to Cadmo. In some legends, the necklace is associated with a garment, which would also have been a wedding present. The necklace was also called the necklace of Eriphila.
After serving Ares for a year, or according to other versions, for eight years, Cadmo became king of Thebes and Zeus married him to Harmonia, daughter of Ares and Aphrodite.
Cadmo gave, as a wedding gift, a necklace and a garment, which had been made by Hephaestus; according to some versions, Hephaestus himself had given these gifts to Cadmo, or, according to Ferecides of Leros, the one who delivered it was Europa, who had received it from Zeus.
Pausanias only mentions that Hephaestus made the necklace, and that the one who first received it as a gift was Harmonia.
When Polynices was expelled from Thebes by his brother Aetheocles, he took the necklace and Harmonia's clothes to Argos. Polynices, at the suggestion of Iphis, son of Alector, used the necklace to bribe Eriphila, wife of Amphiarau, and get her to convince her husband to participate in the expedition against Thebes (the Seven against Thebes).
Amphiarau, forced to go to war, commanded his sons to kill their own mother and march against Thebes. According to Pausanias, from then on the necklace was called Eriphila's necklace.
After the second expedition against Thebes (the Epigonians), Alcmeon, son of Amphiarau, discovered that his mother had again been bribed to go to war, and he killed Eriphila. After being purified by Phegeus, king of Psophis, Alcmeon married Arsinoe, daughter of Phegeus, and gave her, as a gift, the necklace and garment of Harmonia.
The land, however, became barren because of Alcmeon and he, following the oracle, eventually stopped in the lands bordered by the river Aqueloo, received Calírroe, daughter of the river-god, as his wife, and settled a region in the meanders of the river.
Alcmeon and Chalírroe had two sons, Amphoterus and Acarnan, from whom the name of Acarnania is derived. However, Chalírroe wished to have the necklace and garment, and said she would not live with Alcmeon if she did not have them; Alcmeon returned to Psophis and lied to Phegeus, saying that he would only be free of his madness if he took the necklace the garment to Delphi.
Phegeus believed him, but a servant let slip that Alcmiram was taking the necklace and clothes to Chalírroe. Phegeus commanded his sons, and they killed Alcmiram, then took Arsinoe, in a chest, to Tegea, to be Agapenor's slave, accusing her of having murdered Alcmiram.
The version of the story, told by Pausanias, diverges on this point: after murdering Alcmeon by treason, Themene and Axion, the sons of Phegeus, dedicated the necklace to the god of Delphi, and went on to reign in the city called Phegia; they did not take part in the Trojan War because the leaders of the Argives were their enemies, because of their kinship with Alcmeon.
Chalírroe, because of Alcmeon's demise and being courted by Zeus, asked the god to make her sons adults so that they could avenge their father's death. Amphoterus and Acarnan, now adults, arrived at Agapenor's house at the same moment that Pronous and Agenor, sons of Phegeus, arrived, on their journey to take the necklace and clothes to Delphi.
The sons of Alcmeon killed the sons of Phegeus, went to Psophis, and killed Phegeus and his wife, then fled to Thegea, where they escaped with help from the townspeople and some Argives.
Following Aqueloo's guidance, Amphoterus and Acarnan went to Delphi, and dedicated the necklace and clothing there. They then went to Epirus, gathered settlers, and colonized Acarnania.
The necklace was plundered from Delphi by the tyrants of Phocida; in the time of Pausanias, it was said to be in an old shrine of Adonis and Aphrodite in Amathus, a city in Cyprus.
Pausanias, however, does not believe it to be the same necklace, because the necklace at Amathus was made of green gems set in gold, while the necklace given to Eriphila would, according to Homer, be entirely of gold.