Plato, Letters 332a

ποθεν ὀθνείων οὔτε ἀδελφῶν, οὓς ἔθρεψέν τε αὐτὸς νεωτέρους ὄντας, ἔκ τε ἰδιωτῶν ἄρχοντας καὶ ἐκ πενήτων πλουσίους ἐπεποιήκει διαφερόντως. τούτων κοινωνὸν τῆς ἀρχῆς οὐδένα οἷός τʼ ἦν πειθοῖ καὶ διδαχῇ καὶ εὐεργεσίαις καὶ συγγενείαις ἀπεργασάμενος ποιήσασθαι, Δαρείου δὲ ἑπταπλασίῳ φαυλότερος ἐγένετο, ὃς οὐκ ἀδελφοῖς πιστεύσας οὐδʼ ὑφʼ αὑτοῦ τραφεῖσιν, κοινωνοῖς δὲ μόνον τῆς τοῦ Μήδου τε

or men of his own kin whom he himself had reared up in their youth and had raised from a private position to one of authority and from a state of poverty to surpassing wealth. Neither by persuasion nor instruction, neither by benefits nor by ties of kindred, was he able to make any one of them worthy of a share in his government. Thus he was seven times more unhappy than Darius who trusted men who neither were his brothers nor reared up by himself but merely colleagues who had helped him to crush the Mede and the Eunuch; and he divided amongst them seven provinces,