Total civilizational collapse is unusual. In the West, continuity exists between the Roman past and our contemporary states, despite the invasions of “barbarian” groups. The Franks, that ancient people who settled Roman Gaul, were shaped by Roman culture into the people we now know as the French. But what about instances in which there is no continuity—in which a civilization vanishes, and all that is left is a layer of ash? This is what happen…