Passage 5.3.5
καὶ ἐπὶ Ἠλείου βασιλεύοντος ἐν Ἤλιδι, τηνικαῦτα ὁ Δωριέων στόλος σὺν τοῖς Ἀριστομάχου παισὶν ἠθροίζετο ἐπὶ καθόδῳ τῇ ἐς Πελοπόννησον. γίνεται δὲ τοῖς βασιλεῦσιν αὐτῶν λόγιον τόδε, ἡγεμόνα τῆς καθόδου ποιεῖσθαι τὸν τριόφθαλμον. ἀποροῦσι δέ σφισιν ὅ τι ὁ χρησμὸς ἐθέλοι συνέτυχεν ἐλαύνων ἀνὴρ ἡμίονον, ὁ δὲ ἕτερος διέφθαρτο τῷ ἡμιόνῳ τῶν ὀφθαλμῶν·
During the reign of Eleius in Elis, at that time the Dorian expedition under the sons of Aristomachus was assembling for its descent into the Peloponnesus. The following oracle was delivered to their kings: they should select as leader of the descent the one who possessed three eyes. While they were in perplexity as to the oracle's meaning, a man driving a mule happened to encounter them; one of the mule's eyes had been lost.