Μειράκιον Ἐρετρικὸν προσεφοίτησε Ζήνωνι πλείονος χρόνου, ἔστ’ εἰς ἄνδρας ἀφίκετο. ὕστερον οὖν εἰς τὴν Ἐρετρίαν ἐπανῆλθεν, καὶ αὐτὸν ὁ πατὴρ ἤρετο ὅ τι ἄρα μάθοι σοφὸν ἐν τῇ τοσαύτῃ διατριβῇ τοῦ χρόνου. ὁ δὲ ἔφη δείξειν, καὶ οὐκ εἰς μακρὰν ἔδρασε τοῦτο. χαλεπήναντος γὰρ αὐτῷ τοῦ πατρὸς καὶ τέλος πληγὰς ἐκτείναντος, ὁ δὲ τὴν ἡσυχίαν ἀγαγὼν καὶ ἐγκαρτερήσας τοῦτο ἔφη μεμαθηκέναι, φέρειν ὀργὴν πατέρων καὶ μὴ ἀγανακτεῖν.
(Aelian, Var. Hist. 9.33b)
A boy from Eretria attended Zeno’s school over quite a long period, until reaching maturity. After that he returned to Eretria and his father asked him what wisdom he had learned in such a long time. The boy said he would show him, and soon did so. When his father became annoyed and finally beat him, he remained calm and patient and said that what he had learned was to endure the anger of parents and not to lose his temper. (tr. Nigel G. Wilson)