Plato, Laws 810b

μάνθανε. γράμματα μὲν τοίνυν χρὴ τὸ μέχρι τοῦ γράψαι τε καὶ ἀναγνῶναι δυνατὸν εἶναι διαπονεῖν· πρὸς τάχος δὲ ἢ κάλλος ἀπηκριβῶσθαί τισιν, οἷς μὴ φύσις ἐπέσπευσεν ἐν τοῖς τεταγμένοις ἔτεσιν, χαίρειν ἐᾶν. πρὸς δὲ δὴ μαθήματα ἄλυρα ποιητῶν κείμενα ἐν γράμμασι, τοῖς μὲν μετὰ μέτρων, τοῖς δʼ ἄνευ ῥυθμῶν τμημάτων, ἃ δὴ συγγράμματα κατὰ λόγον εἰρημένα μόνον, τητώμενα ῥυθμοῦ τε καὶ ἁρμονίας, σφαλερὰ

They must work at letters sufficiently to be able to read and write. But superior speed or beauty of handwriting need not be required in the case of those whose progress within the appointed period is too slow. With regard to lessons in reading, there are written compositions not set to music, whether in meter or without rhythmical divisions—compositions merely uttered in prose, void of rhythm and harmony;