Plato, Letters 363e

Ἰατροκλῆς, ὁ μετὰ Μυρωνίδου τότε ἐλεύθερος ἀφεθεὶς ὑπʼ ἐμοῦ, πλεῖ νῦν μετὰ τῶν πεμπομένων παρʼ ἐμοῦ· ἔμμισθον οὖν που αὐτὸν κατάστησον ὡς ὄντα σοι εὔνουν, καὶ ἄν τι βούλῃ, αὐτῷ χρῷ. καὶ τὴν ἐπιστολὴν ἢ αὐτὴν ἢ ὑπόμνημα αὐτῆς σῷζέ τε, καὶ ὁ αὐτὸς ἴσθι.

Iatrocles, the man whom I released on that occasion, along with Myronides, is now sailing with the things that I am sending: I ask you, then, to give him some paid post, as he is well-disposed towards you, and employ him for whatever you wish. Preserve also this letter, either itself or a precis of it, and continue as you are.