The fall of the Roman Empire was because of the outside and external invasion from the Huns, because of political corruption, economic troubles, overexpansion, military overspending, and the weakening of Rome's military. Hope this helps.
History specialists of the present era notice, as elements that caused the end of the Empire, the number of soldiers and their quality under the command of the Empire, the wellbeing and quantities of the Roman people, the quality of the economy, the capability of the Emperor, the religious changes of the period and the effectiveness of their government. The frequent attacks by barbarians groups who were outside the Greco-Roman culture was also an important factor. The explanations behind the fall are one of the primary subjects of the historiography of that time and extraordinary discussions on the topic are still frequent about the disappointment of the Roman State as a political element.
