Antiphera

In Greek mythology, Antiphera (Ἀντιφέρα) is a slave woman from Aetolia in the service of Athamas and Ino, a king and queen in Boeotia. Antiphera caught the eye of Athamas, and thus incurred the wrath of his wife Ino.

Mythology
Antiphera was an Aetolian woman who served as a slave for the royal couple of Boeotia, King Athamas and Queen Ino. Ino and Athamas had children together, but he soon initiated sexual relations with the slave woman which he tried to keep secret. Nevertheless his wife Ino found out, and in her jealousy-induced rage, she took her anger out on Melicertes, one her sons by Athamas, by killing him.

This story was used in classical antiquity to explain why slave women were forbidden from entering the shrine of Mater Matuta (the Roman equivalent of the goddess Ino/Leucothea), and the women who brought a single female slave with them would beat and slap them on the head; meanwhile in Chaeronea the guardian of the temple would take a whip and shout "Let no slave enter, nor any Aetolian, man or woman!" while outside Leucothea's temple.

Joseph Fontenrose compared this story to the myths of Aëdon and Procne, both royal women who killed their sons Itylus/Itys in order to take revenge against their unfaithful husbands Zethus and Tereus/Polytechnus.