Passage 4.33.7
διαβάντων δὲ Ἠλέκτραν Ἀχαΐα τε ὀνομαζομένη πηγὴ καὶ πόλεώς ἐστιν ἐρείπια Δωρίου. πεποίηκε δὲ Ὅμηρος μὲν Θαμύριδι ἐνταῦθα ἐν τῷ Δωρίῳ γενέσθαι τὴν συμφοράν, ὅτι καὶ αὐτὰς Μούσας νικήσειν ἔφασκεν ᾀδούσας· Πρόδικος δὲ Φωκαεὺς---εἰ δὴ τούτου τὰ ἐς τὴν Μινυάδα ἔπη---προσκεῖσθαί φησι Θαμύριδι ἐν Ἅιδου δίκην τοῦ ἐς τὰς Μούσας αὐχήματος. διεφθάρη δὲ ὁ Θάμυρις ἐμοὶ δοκεῖν ὑπὸ νόσου τοὺς ὀφθαλμούς, τὸ δὲ αὐτὸ καὶ Ὁμήρῳ συνέπεσεν ὕστερον· ἀλλʼ ὁ μὲν καὶ ἐς ἅπαν διετέλει ποιῶν, οὐ γάρ τι εἶκε τῇ συμφορᾷ, Θάμυρις δὲ καὶ τὴν ᾠδὴν ὑπὸ κακοῦ τοῦ παρόντος ἐξέλιπεν.
After crossing the river Elektra, there is a spring called Achaia and the ruins of the city Dorium. Homer has described Dorium as the place where the calamity befell Thamyris, because he boasted that he could surpass even the Muses in singing. Prodicus of Phocaea—if indeed the verses belonging to the "Minyad" are his—relates that Thamyris in Hades endured punishment for his boastfulness against the Muses. As it seems to me, Thamyris lost his sight due to illness, the same misfortune that later befell Homer himself. But Homer continued to compose poetry throughout his life, as he in no way yielded to his misfortune, whereas Thamyris, overwhelmed by his adversity, ceased entirely from song.