Marcus Aurelius, Meditations 7.49
τὰ προγεγονότα ἀναθεωρεῖν, τὰς τοσαύτας τῶν ἡγεμονιῶν μεταβολάς. ἔξεστι καὶ τὰ ἐσόμενα προεφορᾶν· ὁμοειδῆ γὰρ πάντως ἔσται καὶ οὐχ οἷόν τε ἐκβῆναι τοῦ ῥυθμοῦ τῶν νῦν γινομένων, ὅθεν καὶ ἴσον τὸ τεσσαράκοντα ἔτεσιν ἱστορῆσαι τὸν ἀνθρώπινον βίον τῷ ἐπὶ ἔτη μύρια· τί γὰρ πλέον ὄψει;
Contemplate the events of the past – such great changes in political supremacies – and it becomes possible to foresee the events of the future. For they will be of just the same forms, and cannot turn out differently from the pattern of events happening in the present; therefore observing human life for forty years is the same as for ten thousand years. What more will you see?