Plato, Laws 821c

νὴ τὸν Δία, ὦ ξένε, ἀληθὲς τοῦτο λέγεις· ἐν γὰρ δὴ τῷ βίῳ πολλάκις ἑώρακα καὶ αὐτὸς τόν τε Ἑωσφόρον καὶ τὸν Ἕσπερον καὶ ἄλλους τινὰς οὐδέποτε ἰόντας εἰς τὸν αὐτὸν δρόμον ἀλλὰ πάντῃ πλανωμένους, τὸν δὲ ἥλιόν που καὶ σελήνην δρῶντας ταῦθʼ ἃ ἀεὶ πάντες συνεπιστάμεθα. ταῦτʼ ἔστι τοίνυν, ὦ Μέγιλλέ τε καὶ Κλεινία, νῦν ἃ δή φημι δεῖν περὶ θεῶν τῶν κατʼ οὐρανὸν τούς γε ἡμετέρους

Yes, by Zeus, Stranger, that is true; for I, during my life, have often noticed how Phosphorus and Hesperus and other stars never travel on the same course, but wander all ways; but as to the Sun and Moon, we all know that they are constantly doing this. It is precisely for this reason, Megillus and Clinias, that I now assert that our citizens and our children ought to learn so much concerning all these facts about the gods of Heaven