Aelian, Varia Historia 3.19
“It is reported that the first difference between Plato and Aristotle developed for the following reasons. Plato was displeased with Aristotle’s life, and in the clothing he selected. See, Aristotle dressed in well-made clothes and shoes; he also had his haircut in a manner disliked by Plato; he also took pride in wearing many rings. His face, moreover, bore a certain aspect of derision; and within this face, an untimely talkativeness brought his character into question too. All these characteristics are obviously foreign to a philosopher. When Plato saw them, he was repelled by the man and preferred Xenocrates, Speusippos, Amykles, and others. These men received his respect and regular conversation.
When Xenocrates was out of town to visit his home, Aristotle set upon Plato and made a chorus of his companions around him with Mnason of Phocis and other similar men. Speusippus was ill and was incapable of walking with Plato who was already eighty years old. Thanks to his age, he had lost some parts of his memory. Aristotle plotted against him and set upon him: he questioned him rather aggressively and in the manner of refutation, which was clearly unjust and unsympathetic. Because of this, Plato stopped going for his walk outside; he walked inside with his friends.”
Λέγεται τὴν διαφορὰν ᾿Αριστοτέλους πρὸς Πλάτωνα τὴν πρώτην ἐκ τούτων γενέσθαι. οὐκ ἠρέσκετο τῷ βίῳ αὐτοῦ ὁ Πλάτων οὐδὲ τῇ κατασκευῇ τῇ περὶ τὸ σῶμα. καὶ γὰρ ἐσθῆτι ἐχρῆτο περιέργῳ ὁ ᾿Αριστοτέλης καὶ ὑποδέσει, καὶ κουρὰν δὲ ἐκείρετο καὶ ταύτην ἀήθη Πλάτωνι, καὶ δακτυλίους δὲ πολλοὺς φορῶν ἐκαλλύνετο ἐπὶ τούτῳ· καὶ μωκία δέ τις ἦν αὐτοῦ περὶ τὸ πρόσωπον, καὶ ἄκαιρος στωμυλία λαλοῦντος κατηγόρει καὶ αὕτη τὸν τρόπον αὐτοῦ. πάντα δὲ ταῦτα ὡς ἔστιν ἀλλότρια φιλοσόφου, δῆλον. ἅπερ οὖν ὁρῶν ὁ Πλάτων οὐ προσίετο τὸν ἄνδρα, προετίμα δὲ αὐτοῦ Ξενοκράτην καὶ Σπεύσιππον καὶ ᾿Αμύκλαν καὶ ἄλλους, τῇ τε λοιπῇ δεξιούμενος αὐτοὺς τιμῇ καὶ οὖν καὶ τῇ κοινωνίᾳ τῶν λόγων.
ἀποδημίας δὲ γενομένης ποτὲ τῷ Ξενοκράτει ἐς τὴν πατρίδα, ἐπέθετο τῷ Πλάτωνι ὁ ᾿Αριστοτέλης, χορόν τινα τῶν ὁμιλητῶν τῶν ἑαυτοῦ περιστησάμενος, ὧν ἦν Μνάσων τε ὁ Φωκεὺς καὶ ἄλλοι τοιοῦτοι. ἐνόσει δὲ τότε ὁ Σπεύσιππος, καὶ διὰ ταῦτα ἀδύνατος ἦν συμβαδίζειν τῷ Πλάτωνι. ὁ δὲ Πλάτων ὀγδοήκοντα ἔτη ἐγεγόνει, καὶ ὁμοῦ τι διὰ τὴν ἡλικίαν ἐπελελοίπει τὰ τῆς μνήμης αὐτόν. ἐπιθέμενος οὖν αὐτῷ καὶ ἐπιβουλεύων ὁ ᾿Αριστοτέλης, καὶ φιλοτίμως πάνυ τὰς ἐρωτήσεις ποιούμενος καὶ τρόπον τινὰ καὶ ἐλεγκτικῶς, ἀδικῶν ἅμα καὶ ἀγνωμονῶν ἦν δῆλος· καὶ διὰ ταῦτα ἀποστὰς ὁ Πλάτων τοῦ ἔξω περιπάτου, ἔνδον ἐβάδιζε σὺν τοῖς ἑταίροις.
Aelian, Varia Historia 4.9
“Plato used to call Aristotle Pôlos [the Foal]. What did he wish with that name? Everyone knows that a foal, when it has had its fill of baby’s milk, kicks its mother. Thus Plato was signaling a certain ingratitude on Aristotle’ part. Indeed, Aristotle received the greatest seeds of Philosophy from Plato and then, though he was filled to the brim with the best ideas, he broke with Plato rebelliously. He founded his own house, took his friends on Plato’s walk, and set himself up to be Plato’s rival.”
῾Ο Πλάτων τὸν ᾿Αριστοτέλη ἐκάλει Πῶλον. τί δὲ ἐβούλετο αὐτῷ τὸ ὄνομα ἐκεῖνο; δηλονότι ὡμολόγηται τὸν πῶλον, ὅταν κορεσθῇ τοῦ μητρῴου γάλακτος, λακτίζειν τὴν μητέρα. ᾐνίττετο οὖν καὶ ὁ Πλάτων ἀχαριστίαν τινὰ τοῦ ᾿Αριστοτέλους. καὶ γὰρ ἐκεῖνος μέγιστα ἐς φιλοσοφίαν παρὰ Πλάτωνος λαβὼν σπέρματα καὶ ἐφόδια, εἶτα ὑποπλησθεὶς τῶν ἀρίστων καὶ ἀφηνιάσας, ἀντῳκοδόμησεν αὐτῷ διατριβὴν καὶ ἀντιπαρεξήγαγεν ἐν τῷ περιπάτῳ ἑταίρους ἔχων καὶ ὁμιλητάς, καὶ ἐγλίχετο ἀντίπαλος εἶναι Πλάτωνι.