Our Oriental Heritage page 265:
For barbarism is always around civilization, amid it and beneath it, rady to engulf it by arms, or mass migration, or unchecked fertility. Barbarism is like the jungle; it never admits its defeat; it waits patiently for centuries to recover the territory it lost.
In this volume, the first, this will be a recurring theme. This starts the chapter on Assyria, the barbarians in the equation, about to pounce on the remains of Babylon.
Those who do not know history are doomed to repeat it. Those who know history issue unheeded warnings to the ignorant and are ignored.