Major transformations of civilization are generally only visible in hindsight, but our present warlords provide us windows on the future through their drills and simulations, like event 201 and the Food Chain Reaction Game, in which John Podesta figured heavily, and ended with the institution of carbon credits and transnational corporations riding off into the sunset with all the pretty girls.
Christian @iceagefarmer, like you, keeps his nose to the grindstone and spits truth. But my point is that the collapse of the Western Roman Empire was not so much a violent takeover as simply immigration by populations that saw Rome as a nicer neighborhood, much as is ongoing in Europe, the USA, and Oz today.
Interestingly, Constantine prepared the Eastern Roman Empire to persist for ~1200 years longer than the West, and perhaps his convention of the Nicene Council was a critical component, much as the Food Chain Reaction Game and Event 201 preface today's evolution of civilization.
Let's hope that forewarned is forearmed as much today as it has been in the past.