Passage 6.5.7
Δαρεῖος δὲ Ἀρταξέρξου παῖς νόθος, ὃς ὁμοῦ τῷ Περσῶν καὶ δήμῳ Σόγδιον καταπαύσας παῖδα Ἀρταξέρξου γνήσιον ἔσχεν ἀντʼ ἐκείνου τὴν ἀρχήν, οὗτος ὡς ἐβασίλευσεν ὁ Δαρεῖος---ἐπυνθάνετο γὰρ τοῦ Πουλυδάμαντος τὰ ἔργα---, πέμπων ἀγγέλους ὑπισχνούμενος δῶρα ἀνέπεισεν αὐτὸν ἐς Σοῦσά τε καὶ ἐς ὄψιν ἀφικέσθαι τὴν αὑτοῦ. ἔνθα δὴ κατὰ πρόκλησιν Περσῶν ἄνδρας τῶν καλουμένων ἀθανάτων ἀριθμὸν τρεῖς ἀθρόους οἱ μονομαχήσαντας ἀπέκτεινεν. ἔργων δὲ τῶν κατειλεγμένων οἱ τὰ μὲν ἐπὶ τῷ βάθρῳ τοῦ ἀνδριάντος ἐν Ὀλυμπίᾳ, τὰ δὲ καὶ δηλούμενά ἐστιν ὑπὸ τοῦ ἐπιγράμματος.
Darius, the illegitimate son of Artaxerxes, who, having suppressed together with the Persian people Sogdianus, the legitimate son of Artaxerxes, obtained the throne in his stead—this Darius, after he had become king, having heard about the deeds of Polydamas, sent ambassadors promising him gifts, and persuaded Polydamas to come to Susa and appear before him. There, at the challenge of the Persians, Polydamas killed in single combat, simultaneously, three men of those called "Immortals." Of the deeds recounted about him, some are recorded upon the pedestal of his statue at Olympia, while others are indicated by the inscription.