Aeacus (Greek: Αιακός, transl.: Aiakós), in Greek mythology, is the son of Zeus and the nymph Egina, daughter of the river-god Asopo.
Egina was the daughter of Asopo and Metope, daughter of the river-god Ladon; Asopo and Metope had two sons, Ismeno and Pelagon, and twenty daughters, one of her sisters was Salamis.
Abduction of Egina
Zeus convinced Egina, and Asopos, not having information about his daughter, ended up in Corinth. Sisyphus knew what had happened, and only informed Asopos after he gave Corinth a fountain; because of this Sisyphus was punished in Hades.
Zeus took her to the island of Delos, where she gave birth to Aeacus. According to Pausanias and Pseudo-Apolodorus, Zeus took her to an uninhabited island called Oenone; this island later came to be called Egina.
Hera sent a serpent that poisoned the island's water. Éaco then, finding himself helpless due to the lack of men asked Zeus for help, who turned the ants into men. These men came to be called myrmidons, from the Greek myrmekes for ants. According to Apollodorus, Zeus turned the ants into men because Éaco was alone on the island.
Aeacus married Endeis, daughter of Sciron, and had two sons, Peleus and Telamon, but according to Ferecides of Leros, Telamon would not be the son of Aeacus and Endeis, but a friend of Peleus. Aeacus also had a son with Psâmate, daughter of Nereus, called Focus.
Pious by nature, he is loved by the gods who are pleased to fulfill his vows. So, in order to get his island populated, Aeacus asked Zeus to turn the ants of a sacred oak tree into human beings.
This was the origin of the people of the Myrmidons (ant in Greek), of whom Aeacus became king (a different version of the legend states that the island, populated by settlers brought by Aeacus, was decimated by a plague epidemic sent by Hera and that, to replace the dead, Zeus acceded to his son's request by metamorphosing the ants).
Aeacus built around the island of Aegina a belt of walls, which protected it from the pirates' incursions. He would also have helped Posidon and Apollo build the walls of Troy for King Laomedon.
It is said that when the work was finished, three dragons tried to climb the walls, but only one made it to the end. Exactly the one that climbed the wall built by Aeacus. It was thus deduced that these protections would one day be broken through by one of his descendants.
Aeacus had a daughter, Aichimachus, who was the second wife of Ileu (father of Ájax, "the little one") and two sons, Peleus and Télamus (it was Télamus, the companion of Heracles, who went over the walls of Troy in order to avenge the hero), who had a glorious offspring (Achilles, son of Peleus; the "great Ájax," son of Télamus, both heroes of the Trojan War).
From a second union with the Nereid Psamate, Aeacus had a third son, Phocus. It turned out that his first two sons were jealous of Phocus, who had covered himself with laurels by conquering Phocis, and so they decided to kill him during a game of disco. Aeacus, submissive to the divine laws, sentenced these murderous sons to exile.