What's in an Epigraph?

So as you will recall, totally, I am reading The Red and the Black. You know what's great? No? According to the translator Raffel, Stendhal either misquoted or made up most of the epigraphs at the beginning of the chapters: "Professor Jean-Jacques Hamm has concluded that only fifteen of the seventy-five epigraphs in The Red and the Black are correctly and verifiably attributed." I like to think he made them up, especially this one:

And am I to blame
If that's how things are?
--Machiavelli