Harmonia was the wife of Cadmus of Thebes. She was the daughter of either Ares and Aphrodite or Zeus and Electra (the daughter of Atlas). Her name is obvious, whether we interpret it as 'harmony', 'concord', 'union' or 'agreement'.

It is, however, an unexpected name for one who was (in one account) the daughter of the god of war (Ares) and the goddess of love (Aphrodite). One would expect there to be anything but harmony here!