Passage 1.15.3
τελευταῖον δὲ τῆς γραφῆς εἰσιν οἱ μαχεσάμενοι Μαραθῶνι· Βοιωτῶν δὲ οἱ Πλάταιαν ἔχοντες καὶ ὅσον ἦν Ἀττικὸν ἴασιν ἐς χεῖρας τοῖς βαρβάροις. καὶ ταύτῃ μέν ἐστιν ἴσα τὰ παρʼ ἀμφοτέρων ἐς τὸ ἔργον· τὸ δὲ ἔσω τῆς μάχης φεύγοντές εἰσιν οἱ βάρβαροι καὶ ἐς τὸ ἕλος ὠθοῦντες ἀλλήλους, ἔσχαται δὲ τῆς γραφῆς νῆές τε αἱ Φοίνισσαι καὶ τῶν βαρβάρων τοὺς ἐσπίπτοντας ἐς ταύτας φονεύοντες οἱ Ἕλληνες. ἐνταῦθα καὶ Μαραθὼν γεγραμμένος ἐστὶν ἥρως, ἀφʼ οὗ τὸ πεδίον ὠνόμασται, καὶ Θησεὺς ἀνιόντι ἐκ γῆς εἰκασμένος Ἀθηνᾶ τε καὶ Ἡρακλῆς· Μαραθωνίοις γάρ, ὡς αὐτοὶ λέγουσιν, Ἡρακλῆς ἐνομίσθη θεὸς πρώτοις. τῶν μαχομένων δὲ δῆλοι μάλιστά εἰσιν ἐν τῇ γραφῇ Καλλίμαχός τε, ὃς Ἀθηναίοις πολεμαρχεῖν ᾕρητο, καὶ Μιλτιάδης τῶν στρατηγούντων, ἥρως τε Ἔχετλος καλούμενος, οὗ καὶ ὕστερον ποιήσομαι μνήμην.
At the end of the painting are those who fought at Marathon, including the Plataeans from Boeotia and all the forces from Attica who engaged in direct combat against the barbarians. Here the two sides are evenly matched in the fighting. Within the scene of battle itself, the barbarians are depicted fleeing and pushing one another into the marsh. At the very edge of the painting appear the Phoenician ships and the Greeks killing those of the barbarians who rush aboard. Here is painted also the hero Marathon, from whom the plain has taken its name, and Thereus, represented emerging from the earth, as well as Athena and Heracles. For, according to the Marathonian people themselves, they were the first to worship Heracles as a god. Among the combatants shown most prominently in the painting are Callimachus, who was chosen polemarch by the Athenians, Miltiades, one of the generals, and a hero named Echetlos, whom I will have occasion to mention later.