Plutarch, De Iside et Osiride 34

ἥλιον δὲ καὶ σελήνην οὐχ ἅρμασιν ἀλλὰ πλοίοις ὀχήμασι χρωμένους περιπλεῖν φασιν, αἰνιττόμενοι τὴν ἀφʼ ὑγροῦ τροφὴν αὐτῶν καὶ γένεσιν. οἴονται δὲ καὶ Ὅμηρον ὥσπερ Θαλῆν μαθόντα παρʼ Αἰγυπτίων ὕδωρ ἀρχὴν ἁπάντων καὶ γένεσιν τίθεσθαι, τὸν γὰρ Ὠκεανὸν Ὄσιριν εἶναι, τὴν δὲ Τηθὺν Ἶσιν, ὡς τιθηνουμένην πάντα καὶ συνεκτρέφουσαν. καὶ γὰρ Ἕλληνες τὴν τοῦ σπέρματος πρόεσιν ἀπουσίαν καλοῦσι καὶ συνουσίαν τὴν μῖξιν, καὶ τὸν υἱὸν ἀπὸ τοῦ ὕδατος καὶ τοῦ ὗσαι· καὶ τὸν Διόνυσον ὕην ὡς κύριον τῆς ὑγρᾶς φύσεως, οὐχ ἕτερον ὄντα τοῦ Ὀσίριδος καὶ γὰρ τὸν Ὄσιριν Ἑλλάνικος Ὄσιριν ἔοικεν ἀκηκοέναι ὑπὸ τῶν ἱερέων λεγόμενον· οὕτω γὰρ ὀνομάζων διατελεῖ τὸν θεόν, εἰκότως ἀπὸ τῆς φύσεως καὶ τῆς εὑρέσεως.

They say that the sun and moon do not use chariots, but boats in which to sail round in their courses; and by this they intimate that the nourishment and origin of these heavenly bodies is from moisture. They think also that Homer, like Thales, had gained his knowledge from the Egyptians, when he postulated water as the source and origin of all things; for, according to them, Oceanus is Osiris, and Tethys is Isis, since she is the kindly nurse and provider for all things. In fact, the Greeks call emission apousia and coition synousia, and the son (hyios) from water (hydor) and rain (hysai); Dionysus also they call Hyes since he is lord of the nature of moisture; and he is no other than Osiris. In fact, Hellanicus seems to have heard Osiris pronounced Hysiris by the priests, for he regularly spells the name in this way, deriving it, in all probability, from the nature of Osiris and the ceremony of finding him.