Plato, Laws 813b

καθάπερ μουσικῆς τὸ διδασκαλικὸν ὑπόλοιπον ὂν ἀπέδομεν, ὡσαύτως ποιῶμεν καὶ γυμναστικῆς. τοὺς γὰρ παῖδάς τε καὶ τὰς παῖδας ὀρχεῖσθαι δὴ δεῖ καὶ γυμνάζεσθαι μανθάνειν· ἦ γάρ; ναί. τοῖς μὲν τοίνυν παισὶν ὀρχησταί, ταῖς δὲ ὀρχηστρίδες ἂν εἶεν πρὸς τὸ διαπονεῖν οὐκ ἀνεπιτηδειότερον. ἔστω δὴ ταύτῃ. πάλιν δὴ τὸν τὰ πλεῖστα ἕξοντα πράγματα καλῶμεν,

Just as, in the case of music, we have supplied the regulations about tuition that were missing, so also let us now do in the case of gymnastics. Shall we not say that both girls and boys must learn both dancing and gymnastics? Yes. Then for their practices it would be most proper that boys should have dancing-masters, and girls mistresses. I grant it. Let us once more summon the man who will have most of these duties to perform,