Plato, Letters 316c

πόλεις ἐμποδὼν ἐμὲ γεγενῆσθαι. τὴν οὖν ἀρχὴν ὧν εἶπον περὶ προτέρων ἄκουε πρότερον.ἦλθον καλούμενος εἰς Συρακούσας ὑπό τε σοῦ καὶ Δίωνος, τοῦ μὲν δεδοκιμασμένου παρʼ ἐμοὶ καὶ ξένου πάλαι γεγονότος, ἐν ἡλικίᾳ δὲ ὄντος μέσῃ τε καὶ καθεστηκυίᾳ, ὧν δὴ παντάπασιν χρεία τοῖς νοῦν καὶ σμικρὸν κεκτημένοις, μέλλουσιν περὶ τοσούτων ὅσα ἦν τότε τὰ σὰ βουλεύεσθαι, σοῦ δὲ ὄντος μὲν σφόδρα νέου, πολλῆς δὲ ἀπειρίας οὔσης περὶ σὲ τούτων

to the origin of the first of the accusations I have mentioned. It was on your invitation and Dion’s that I came to Syracuse. Dion was a tried comrade of mine and a guest-friend of old standing, and he was a man of staid middle age,—qualities that are specially required by men who possess even a particle of sense when they intend to advise concerning affairs so important as yours then were. You, on the other hand, were extremely young, and in your case I was quite without experience of those points regarding which experience was required,