What are the main threats to the continued survival of humanity? What catastrophes lie ahead? These may seem like uniquely modern questions posed by contemporary thinkers in the growing field of existential risk. Yet, millennia ago, ancient Greek and Roman philosophers were already formulating and debating such questions. While these thinkers had radically different ways of looking at the world and one’s place in it, they all agreed that some form of apocalyptic catastrophe awaited humans in the future.