Reason 3: Political Instability in Roman Empire - Although Rome had some great leaders, most of the other leaders were not. They had inconsistent leadership, which was very insufficient for the empire, causing people to lose faith in the leadership and lose the overall feeling of unity in the empire.
Reason 2: Disease in Roman Empire - The infectious plague killed more than thousands of people in the roman empire,which resulted in a decline of agricultural production, trade, and soldiers. By declining these major parts of the empire it caused economics and protection of the Roman empire to decline.
Reason 1: Religious Conflicts with Roman Empire - When the people in the Roman Empire lost faith in their leaders, their loyalty to the leaders in the Empire and the council begin to fade. Christianity contributed to the reconstruction of the citizens of Rome who were unhappy with their prior way of life with the Roman Empire. The rise of a new faith helped contribute to the empire’s fall. Christianity displaced the polytheistic Roman religion, which viewed the emperor as having a divine status and also changed the focus from the glory of the state onto a sole deity. Because of these reasons citizens revolted due to them not being happy with the unstable Rome Empire, which led them to change religions to Christianity for a new way of life.