Historians have variously dated the final collapse to the sack of Rome in AD410 by the Visigoth king Alaric, the deposing of the last Roman emperor by the German chieftain Odoacer in AD476 and the death of Justinian I, the last Roman emperor to try to reconquer the western half of the empire, in AD565.
The reasons for the fall of the empire include military overreach, invasion by emboldened tribes of Huns and Visigoths from northern and central Europe, inflation, corruption and political incompetence.
While historians have examined dozens of reasons for the decline of the greatest empire the world had ever seen, homosexuality is not one of them.
"No historian is going to argue that debauchery brought about the end of the empire," said Philip Matyszak, a historian and author with a doctorate in Roman history from Oxford University.
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"At the end of the imperial period, Carthage was one of the great Christian centres of the empire, so it seems odd to claim that it was spreading debauchery. The empire as a whole was becoming ever more Christian. Economic collapse and the arrival of the barbarian hordes had a lot more to do with the end of Roman rule."
In 'The History of the Decline and Fall of the Roman Empire', Edward Gibbon blamed the adoption of Christianity as the official religion and a decline in civic virtue as the reason for the collapse.
The huge cost of maintaining bridges, roads and aqueducts over such a vast territory has also been identified as a contributing factor, as has the expense of maintaining enough legions to subdue and police the empire.
Increases in taxation were also highly unpopular, while increased trade with India and China,