Passage 4.28.4
οὐ πολλῷ δὲ ὕστερον ἔσχον Ἦλιν Μεσσήνιοι, σοφίᾳ τε ὁμοῦ χρησάμενοι καὶ τολμήματι. Ἠλεῖοι γὰρ τὰ μὲν παλαιότατα εὐνομώτατοι Πελοποννησίων ἦσαν· Φιλίππου δὲ τοῦ Ἀμύντου τά τε ἄλλα ὁπόσα εἴρηται κακουργήσαντος τὴν Ἑλλάδα καὶ Ἠλείων τοὺς δυνατοὺς διαφθείραντος χρήμασι, στασιάζουσι πρῶτον τότε Ἠλεῖοι καὶ ἐς ὅπλα, ὡς λέγουσι, χωροῦσι.
Not long afterwards, the Messenians gained Elis through a combination of cleverness and daring. For previously, the Eleans had been the most orderly of the Peloponnesians. But when Philip son of Amyntas, among other acts of wrongdoing inflicted upon Greece, corrupted the influential men of Elis with money, civil strife broke out for the first time among the Eleans, and, as they say, they came to open warfare.