Why did Christianity survive the fall of the Roman Empire?
The Empire by the time of Romulus Augustus was in many ways already essentially ‘medieval’ in function: large fortified manors in the less cultivated regions sprung up to defend the locale where Imperial troops were rare or non-existent, and while it’s true that the clergy had taken over many of the auspices of the Roman government, the decline of contact between the civilized regions of the Empire did lead to a gradual dissolution of Latin civilization.
