Hermias of Atarneus (/ˈhɜːrmiəs/; Greek: Ἑρμίας ὁ Ἀταρνεύς; died 341/0 BC) was a Greek tyrant of Atarneus, and Aristotle's father-in-law.
The first mention of Hermias is as a slave to Eubulus, a Bithynian banker who ruled Atarneus. Hermias eventually won his freedom and inherited the rule of Atarneus. Due to his policies, his control expanded to other neighbouring cities, such as Assos, in Asia Minor.
Pythias (/ˈpɪθiəs/; Greek: Πυθιάς, romanized: Pūthiás), also known as Pythias the Elder, was the adopted daughter of Hermias, ruler of the cities Assos and Atarneus on the Anatolian coast opposite the island of Lesbos. She was also Aristotle's first wife. Hermias was an enemy of Persia and allied with Macedonia. In his will, Aristotle ordered that he be buried next to his wife. From his wording, it is known that Pythias was already dead by the time he wrote his will.