Invasions by Barbarian tribes. The most straightforward theory for Western Rome’s collapse pins the fall on a string of military losses sustained against outside forces.
Economic troubles and overreliance on slave labor. Even as Rome was under attack from outside forces, it was also crumbling from within thanks to a severe financial crisis.
The rise of the Eastern Empire. The fate of Western Rome was partially sealed in the late third century, when the Emperor Diocletian divided the Empire into two halves.
Overexpansion and military overspending. At its height, the Roman Empire stretched from the Atlantic Ocean all the way to the Euphrates River in the Middle East.
