Passage 4.35.5
Ἠπειρῶται δὲ ὡς ἐπαύσαντο βασιλεύεσθαι, τά τε ἄλλα ὁ δῆμος ὕβριζε καὶ ἀκροᾶσθαι τῶν ἐν ταῖς ἀρχαῖς ὑπερεώρων· καὶ σφᾶς οἱ Ἰλλυριοὶ τὰ πρὸς τοῦ Ἰονίου τὴν Ἤπειρον ὑπεροικοῦντες παρεστήσαντο ἐξ ἐπιδρομῆς. οὐ γάρ πω δημοκρατίαν ἴσμεν ἄλλους γε ἢ Ἀθηναίους αὐξήσαντας, Ἀθηναῖοι δὲ προήχθησαν ἐπὶ μέγα ἀπʼ αὐτῆς· συνέσει γὰρ οἰκείᾳ τὸ Ἑλληνικὸν ὑπερεβάλλοντο καὶ νόμοις τοῖς καθεστηκόσιν ἐλάχιστα ἠπείθουν.
When the people of Epirus ceased to be ruled by kings, the common folk began to act insolently in many respects and openly disregarded the commands of their magistrates. Thus the Illyrians, who inhabit the region of Epirus bordering on the Ionian Sea, conquered them through invasion. Indeed, as yet we know of no democracy besides that of Athens that flourished: and the Athenians attained greatness precisely through democracy. For they surpassed the rest of the Greeks by reason of their own good sense, and they least disobeyed the established laws.