King Amphiaraus (AM-fee-uh-RAY-us, "doubly cursed") of Argos sailed with the Argonauts and was one of the Seven Against Thebes, the warriors gathered by King Adrastus and Polynices to reclaim the throne of Thebes for the latter. He was the son of King Oicles and Hypermnestra. A descendant of the seer and healer Melampus, like his ancestor he was a prophet. He was married to Eriphyle, sister of Adrastus, and both men ruled Argos together.

Amphiaraus knew that the expedition against Thebes was bad news (he was a prophet, after all) and refused to participate. But, like so many other reluctant Greek warriors, he was tricked into it. His wife bribed him with the magical necklace of Harmonia, which apparently was incentive enough to risk his neck for, no pun intended. The necklace was from Polynices, handed down from Cadmus, the first king of Thebes and husband of Harmonia.

When the siege of Thebes went badly, as he expected, he turned his chariot around and bolted. Poriclymenus, a Theban defender, was hot on his trail, but Zeus split the earth open and swallowed Amphiaraus, Amphiaraus’ chariot, and his charioteer Baton and sent them to the underworld before Amphiaraus could be killed by the warrior.

Before he left, he made his sons Amphilochus and Alcmaeon swear to avenge his death, and to kill their mother for getting him killed to boot. They joined the Epigonoi and succeeded fulfilling their father’s wishes.