Fall of the Western Empire

The City of God

Augustine of Hippo

Written after the sack of Rome in 410 to answer pagans blaming the disaster on Christianity, it argues that no earthly city was ever eternal and separates the fate of the empire from the fate of the faith — the argument that let Latin Christianity outlive the state that had adopted it.

The History of the Decline and Fall of the Roman Empire

Edward Gibbon

Argues Rome fell to a slow internal corrosion of civic virtue compounded by Christianity rather than to any single external blow — a thesis modern historians largely reject, though it still frames the question.

Assumes a working outline of Roman history, and that Gibbon's judgements are as much the subject as the events