While you're there, read this article on the Fall of Rome.
Roman historians recognized what they considered to be a decay in the traditional Roman character from the late Republic onwards. Symptoms included a falling birth-rate, a growing gap between rich and poor, and declining attachment to ancient traditions. Modern historians have tended to focus on economic and political changes, but this new theory suggests that the root cause was, in fact, a mass change in temperament driven by prosperity.Sounds familiar.

