Herodotus, Histories 2.53

Ἡσίοδον γὰρ καὶ Ὅμηρον ἡλικίην τετρακοσίοισι ἔτεσι δοκέω μευ πρεσβύτερους γενέσθαι καὶ οὐ πλέοσι. οὗτοι δέ εἰσιν οἱ ποιήσαντες θεογονίην Ἕλλησι καὶ τοῖσι θεοῖσι τὰς ἐπωνυμίας δόντες καὶ τιμάς τε καὶ τέχνας διελόντες καὶ εἴδεα αὐτῶν σημήναντες. οἱ δὲ πρότερον ποιηταὶ λεγόμενοι τούτων τῶν ἀνδρῶν γενέσθαι ὕστερον, ἔμοιγε δοκέειν, ἐγένοντο.

For I think that Hesiod and Homer in age were older than me by four hundred years and no more. It is they who made the theogony for the Greeks and gave the gods their eponyms and distributed their honours and skills and indicated their forms. The poets who are said to be older than these men came later, it seems to me.

Relevant guides Hesiod