Enigma of an Autumn Afternoon

Many years ago I wrote down this quote from Flaubert:

The melancholy of the antique world seems to me more profound than that of the moderns, all of whom more or less imply that beyond the dark void lies immortality. But for the ancients that black hole is infinity itself; their dreams loom and vanish against a background of immutable ebony. No crying out, no convulsions - nothing but the fixity of a pensive gaze ...

I wanted to use it as a epigraph for a book but I had, and have, no idea of what the book in fact might be. Or might have been, I should say. Then I lost the quote ... a few days ago it recurred in my mind but I couldn't exactly remember it. So I went looking on the web, and found it, eventually, here.

It comes from a letter Flaubert wrote to Madame Roger des Genettes and there's more:

... just when the gods had ceased to be and the Christ had not yet come, there was a unique moment in history, between Cicero and Marcus Aurelius, when man stood alone. Nowhere else do I find that particular grandeur.

This, it turns out, was (part of?) M. Yourcenar’s inspiration for her book Memoirs of Hadrian though I don't know if she uses it as an epigraph or not, never having read the book. Perhaps I should. Somehow, though this wasn't the case when I first copied it down, the remark now makes me think of this: