It was divided into classes more formally than ours is today. It would be more like England now. It was an empire that grew to cover most of the civilized world and a lot of what wasn't civilized. As it grew, it's citizens became less responsible, and less productive. Eventually it depended on surrounding civilizations for its economic maintenance. That's when it began to collapse. Finally the surrounding cultures closed in because of climate changes. They began raiding the empire when it refused to assign more territories to them from within it's empire.
Some of that fits, some doesn't. We have external overpopulating cultures closing in. It's not climate yet but it will be as we go deeper into the periodic large (100,000 year) ice age, or one of the mini ice ages between.
Some of that fits, some doesn't. We have external overpopulating cultures closing in. It's not climate yet but it will be as we go deeper into the periodic large (100,000 year) ice age, or one of the mini ice ages between.