Plato, Letters 357b

διεπολέμησαν πρὸς τὴν τυραννίδα, τοὺς δʼ ἔμπροσθεν οἰκητὰς τῶν Ἑλληνικῶν τόπων εἰς τὰς ἀρχαίας καὶ πατρῴας οἰκήσεις κατοικίσας· ταὐτὰ δὲ ταῦτα καὶ νῦν πᾶσιν συμβουλεύω κοινῇ διανοηθῆναι καὶ πράττειν τε καὶ παρακαλεῖν ἐπὶ ταύτας τὰς πράξεις πάντας, τὸν μὴ ʼθέλοντα δὲ πολέμιον ἡγεῖσθαι κοινῇ. ἔστιν δὲ ταῦτα οὐκ ἀδύνατα· ἃ γὰρ ἐν δυοῖν τε ὄντα ψυχαῖν τυγχάνει καὶ λογισαμένοις εὑρεῖν βέλτιστα ἑτοίμως ἔχει, ταῦτα δὲ σχεδὸν ὁ κρίνων ἀδύνατα

and restoring the former occupiers of the Greek regions to their ancient and ancestral homes. And now likewise I counsel you all with one accord to adopt and execute these same plans, and to summon all to this task, and to count him who refuses as a common enemy. Nor is such a course impossible; for when plans actually exist in two souls, and when they are readily perceived upon reflection to be the best, he who pronounces such plans impossible is hardly a man of understanding. And by the two souls