Plato, Laws 755b

ὑπερβὰς ἑβδομήκοντα ζῇ, μηκέτι ἐν τούτοις τοῖς ἄρχουσι τὴν τηλικαύτην ἀρχὴν ὡς ἄρξων διανοηθήτω.τὰ μὲν οὖν περὶ τῶν νομοφυλάκων ταῦτα εἰρήσθω προστάγματα τρία, προϊόντων δὲ εἰς τοὔμπροσθε τῶν νόμων ἕκαστος προστάξει τούτοις τοῖς ἀνδράσιν ὧντινων αὐτοὺς δεῖ πρὸς τοῖς νῦν εἰρημένοις προσεπιμελεῖσθαι· νῦν δʼ ἑξῆς ἄλλων ἀρχῶν αἱρέσεως πέρι λέγοιμεν ἄν. δεῖ γὰρ δὴ τὰ μετὰ ταῦτα στρατηγοὺς αἱρεῖσθαι, καὶ τούτοις εἰς τὸν πόλεμον

beyond the age of seventy, he must no longer fancy that he can remain among these officials holding an office of such high importance. So, for the Law-wardens, let us state that these three duties are imposed on them, and as we proceed with the laws, each fresh law will impose upon these men whatever additional duties they ought to be charged with beyond those now stated. And now we may go on to describe the selection of the other officials. Commanders must be selected next,