Passage 5.1.3
τοὺς Ἠλείους ἴσμεν ἐκ Καλυδῶνος διαβεβηκότας καὶ Αἰτωλίας τῆς ἄλλης· τὰ δὲ ἔτι παλαιότερα ἐς αὐτοὺς τοιάδε εὕρισκον. βασιλεῦσαι πρῶτον ἐν τῇ γῇ ταύτῃ λέγουσιν Ἀέθλιον, παῖδα δὲ αὐτὸν Διός τε εἶναι καὶ Πρωτογενείας τῆς Δευκαλίωνος, Ἀεθλίου δὲ Ἐνδυμίωνα γενέσθαι·
We know that the Eleans came across from Calydon and the rest of Aetolia; but concerning yet earlier times, I discovered the following about them. They say that the first to rule in this land was Aethlius, who was the son of Zeus and of Protogeneia, daughter of Deucalion, and that Endymion was the son of Aethlius.