The barbarians overtook Rome when Rome was at a weak point.
Rome was weak "morally."
It weakened Rome because of the Great Fire caused by communist and atheist.
The outside groups such as German Barbarians (no offence to any current germans) and Mongolians wanted to invade rome because rome had alot of territory and at the time seemed to be a weak target with lots of gold. The Vandals sacked Rome in 455 A.D. They did it because Rome was weak.
it made all of the soilders weak
The Northern Frontier was a weak spot of the Roman Empire.
Augustus was born
Rome became weak after a deadly plague that killed about 2000 people per day. Some time after that Rome fell to the Gauls. (Almost like the story of Asterix and Obelix)
A weak or impotent leader invited competitors to try to takeover. With the internal contests, it was easier for the incoming Eurasian peoples to take over.
Cleopatra could in no way hurt Rome. She was a minor queen of a weak country with no military to speak of. However she actually helped Rome. By her defeat she enabled the civil wars to end and the Pax Romana to begin.
The senators went politically weak when they tried to regain power of Rome. They lost most of its political power and prestige.
The Principate.