Ironic indeed! The modern sense is very modern. I recall quite a few contemporary-to-him pamphlets that accused Thomas Hobbes of "atheism" simply because the God he described didn't accord with acceptable Christian orthodoxy, though he too would probably not be considered an atheist by modern lights. (Just one example; there are countless others.)

I must confess that the ancient usage makes more sense to me: an atheist is someone who denies *any* of the Gods. Or in the words of the tired old joke, "When you've already disbelieved in all the other Gods, what's one more?"

And thank you for the tip to the Paradiso. It's been many a long year since I last read it. I agree: Dante is picking up on a long tradition, and doing so in his typically eloquent fashion!

My first hook on this bit was instead a few thousand years earlier, to the discussion of the "lots" of the Gods (and of Athene in particular) in Plato's Timaeus, regarding which Proclus has a bit to say. All these, and many more, are highly relevant!