Ante-Nicene Fathers, Vol III:
Tertullian: Part I: Chapter X.

Chapter X.

“You do not worship the gods,” you say; “and you do not offer sacrifices for the emperors.” Well, we do not offer sacrifice for others, for the same reason that we do not for ourselves,—namely, that your gods are not at all the objects of our worship.  So we are accused of sacrilege and treason. This is the chief ground of charge against us—nay, it is the sum-total of our offending; and it is worthy then of being inquired into, if neither prejudice nor injustice be the judge, the one of which has no idea of discovering the truth, and the other simply and at once rejects it. We do not worship your gods, because we know that there are no such beings.  This, therefore, is what you should do:  you should call on us to demonstrate their non-existence, and thereby prove that they have no claim to adoration; for only if your gods were truly so, would there be any obligation to render divine homage to them. And punishment even were due to Christians, if it were made plain that those to whom they refused all worship were indeed divine. But you say, They are gods. We protest and appeal from yourselves to your knowledge; let that judge us; let that condemn us, if it can deny that all these gods of yours were but men. If even it venture to deny that, it will be confuted by its own books of antiquities, from which it has got its information about them, bearing witness to this day, as they plainly do, both of the cities in which they were born, and the countries in which they have left traces of their exploits, as well as where also they are proved to have been buried.  Shall I now, therefore, go over them one by one, so numerous and so various, new and old, barbarian, Grecian, Roman, foreign, captive and adopted, private and common, male and female, rural and urban, naval and military? It were useless even to hunt out all their names: so I may content myself with a compend; and this not for your information, but that you may have what you know brought to your recollection, for undoubtedly you act as if you had forgotten all about them. No one of your gods is earlier than Saturn: from him you trace all your deities, even those of higher rank and better known. What, then, can be proved of the first, will apply to those that follow. So far, then, as books give us information, neither the Greek Diodorus or Thallus, neither Cassius Severus or Cornelius Nepos, nor any writer upon sacred antiquities, have ventured to say that Saturn was any but a man: so far as the question depends on facts, I find none more trustworthy than thosep. 27 —that in Italy itself we have the country in which, after many expeditions, and after having partaken of Attic hospitalities, Saturn settled, obtaining cordial welcome from Janus, or, as the Salii will have it, Janis. The mountain on which he dwelt was called Saturnius; the city he founded is called Saturnia to this day; last of all, the whole of Italy, after having borne the name of Oenotria, was called Saturnia from him.  He first gave you the art of writing, and a stamped coinage, and thence it is he presides over the public treasury.  But if Saturn were a man, he had undoubtedly a human origin; and having a human origin, he was not the offspring of heaven and earth. As his parents were unknown, it was not unnatural that he should be spoken of as the son of those elements from which we might all seem to spring. For who does not speak of heaven and earth as father and mother, in a sort of way of veneration and honour? or from the custom which prevails among us of saying that persons of whom we have no knowledge, or who make a sudden appearance, have fallen from the skies? In this way it came about that Saturn, everywhere a sudden and unlooked-for guest, got everywhere the name of the Heaven-born.  For even the common folk call persons whose stock is unknown, sons of earth. I say nothing of how men in these rude times were wont to act, when they were impressed by the look of any stranger happening to appear among them, as though it were divine, since even at this day men of culture make gods of those whom, a day or two before, they acknowledged to be dead men by their public mourning for them. Let these notices of Saturn, brief as they are, suffice. It will thus also be proved that Jupiter is as certainly a man, as from a man he sprung; and that one after another the whole swarm is mortal like the primal stock.