Passage 5.1.8
Αἰτωλῷ δὲ μετὰ Ἐπειὸν βασιλεύσαντι συνέπεσεν ἐκ Πελοποννήσου φυγεῖν, ὅτι αὐτὸν οἱ Ἄπιδος παῖδες ἐφʼ αἵματι ἀκουσίῳ δίκην εἷλον· Ἆπιν γὰρ τὸν Ἰάσονος ἐκ Παλλαντίου τοῦ Ἀρκάδων ἀπέκτεινεν Αἰτωλὸς ἐπελάσας τὸ ἅρμα τεθέντων ἐπὶ Ἀζᾶνι ἄθλων. ἀπὸ μὲν Αἰτωλοῦ τοῦ Ἐνδυμίωνος οἱ περὶ τὸν Ἀχελῷον οἰκοῦντες ἐκλήθησαν φυγόντος ἐς ταύτην τὴν ἤπειρον, τὴν δὲ Ἐπειῶν ἔσχεν ἀρχὴν Ἠλεῖος, Εὐρυκύδας τε τῆς Ἐνδυμίωνος καὶ---ὅτῳ πιστὰ---πατρὸς ὢν Ποσειδῶνος· καὶ τὸ ὄνομα οἱ ἄνθρωποι τὸ νῦν ἀντὶ Ἐπειῶν ἀπὸ τοῦ Ἠλείου μεταβεβλήκασιν.
After Epeius, Aetolus became king, but he was forced to flee from the Peloponnese because the sons of Apis prosecuted him for involuntary bloodshed. For Aetolus had killed Apis, the son of Jason from Pallantium in Arcadia, by running him over with his chariot during the funeral games held in honor of Azan. Due to the flight of Endymion's son Aetolus into this land, the inhabitants dwelling near the river Achelous received the name Aetolians. When he departed, Eleius succeeded to the kingship of the Epeians. Eleius was the son of Eurycyda, daughter of Endymion, and—if one is to trust such matters—the son of Poseidon. From him, the people changed their name from Epeians to Eleans, the name they bear until this day.