Plato, Laws 694b

καὶ προθύμους αὑτοὺς ἐν τοῖς κινδύνοις παρείχοντο· καὶ εἴ τις αὖ φρόνιμος ἦν ἐν αὐτοῖς καὶ βουλεύειν δυνατός, οὐ φθονεροῦ τοῦ βασιλέως ὄντος, διδόντος δὲ παρρησίαν καὶ τιμῶντος τοὺς εἴς τι δυναμένους συμβουλεύειν, κοινὴν τὴν τοῦ φρονεῖν εἰς τὸ μέσον παρείχετο δύναμιν, καὶ πάντα δὴ τότε ἐπέδωκεν αὐτοῖς διʼ ἐλευθερίαν τε καὶ φιλίαν καὶ νοῦ κοινωνίαν. ἔοικέν γέ πως τὰ λεγόμενα οὕτω γεγονέναι.

towards their officers and showed their devotion in times of danger; and if there was any wise man amongst them, able to give counsel, since the king was not jealous but allowed free speech and respected those who could help at all by their counsel,—such a man had the opportunity of contributing to the common stock the fruit of his wisdom. Consequently, at that time all their affairs made progress, owing to their freedom, friendliness and mutual interchange of reason. Probably that is pretty much the way in which the matters you speak of took place.