Plato, Letters 338c

κατὰ τὴν φιλοσοφίαν τοῖς νέοις πολλὰ τοιαῦτα γιγνόμενα, ὅμως δʼ οὖν ἀσφαλέστερόν μοι ἔδοξεν χαίρειν τότε γε πολλὰ καὶ Δίωνα καὶ Διονύσιον ἐᾶν, καὶ ἀπηχθόμην ἀμφοῖν ἀποκρινάμενος ὅτι γέρων τε εἴην καὶ κατὰ τὰς ὁμολογίας οὐδὲν γίγνοιτο τῶν τὰ νῦν πραττομένων. ἔοικεν δὴ τὸ μετὰ τοῦτο Ἀρχύτης τε παρὰ Διονύσιον ἀφικέσθαι—ἐγὼ γὰρ πρὶν ἀπιέναι ξενίαν καὶ φιλίαν Ἀρχύτῃ καὶ τοῖς ἐν

I was of course well aware that such things often happen to the young in regard to philosophy; but none the less I deemed it safer, at least for the time, to give a wide berth both to Dion and Dionysius, and I angered them both by replying that I was an old man and that none of the steps which were now being taken were in accordance with our compact. Now it seems that after this Archytas arrived at the court of Dionysius; for when I sailed away, I had, before my departure, effected a friendly alliance between Archytas and the Tarentines and Dionysius;