Plato, Laws 800a

ἂν οὐδʼ ἐκεῖνοι παντάπασί γʼ ἂν ἀφεστῶτες εἶεν τοῦ νῦν λεγομένου, καθʼ ὕπνον δὲ οἷόν πού τις ἢ καὶ ὕπαρ ἐγρηγορὼς ὠνείρωξεν μαντευόμενος αὐτό—τὸ δʼ οὖν δόγμα περὶ αὐτοῦ τοῦτʼ ἔστω· παρὰ τὰ δημόσια μέλη τε καὶ ἱερὰ καὶ τὴν τῶν νέων σύμπασαν χορείαν μηδεὶς μᾶλλον ἢ παρʼ ὁντινοῦν ἄλλον τῶν νόμων φθεγγέσθω μηδʼ ἐν ὀρχήσει κινείσθω. καὶ ὁ μὲν τοιοῦτος ἀζήμιος ἀπαλλαττέσθω, τὸν δὲ μὴ πειθόμενον, καθάπερ ἐρρήθη νυνδή, νομοφύλακές τε

so that they, too, perhaps, would not wholly disagree with our present suggestion, but one of them may have divined it vaguely, as in a dream by night or a waking vision: anyhow, let this be the decree on the matter:—In violation of public tunes and sacred songs and the whole choristry of the young, just as in violation of any other nome (law), no person shall utter a note or move a limb in the dance. He that obeys shall be free of all penalty; but he that disobeys shall (as we said just now) be punished by the Law-wardens, the priestesses and the priests.