For more than two thousand years, Rome was a large, powerful, and dominating empire. The ancient kingdom seemed unstoppable, but in just few centuries later, Roman power fell and was obliterated. No one knows exactly how the empire's demise came to be and is still debated today but there are some major factors recognized that caused Rome to fall.
The land of barbarians were located beyond the western border of Rome along Rhine and Danube rivers and would slowly become a serious threat to Rome and eventually led to the fall of the empire. At first, they posed no danger as they were only German farmers that were nomadic because of their poor agricultural skills. The barbarians could not develop a political structure either so they were small and weak compared to Rome. In fact, Rome gained the tribes loyalty by using money, trade, and military honors and make them turn against each other. By the third century, however, the barbarians changed and become more complex, due to the garrisons and merchants that prompted economic and sociopolitical growth in the border tribes. The farmers were introduced Roman agricultural techniques which stabilized their population and the tribes increased in size which led to establishing towns. Since the population became bigger, the tribes created a more organized and complicated political constitution. The barbarians soon had stronger and larger armies and posed a threat of raiding the borders and have a mass migration to Rome.
Another major factor that caused the demise of Rome was the recurrent civil wars between the emperors and usurpers, which are rebels that try to illegally take power, like generals or other officers. These frequent civil wars brought thousands of deaths, disorderly training, and removed manpower supply and caused emperors to focus their concerns on usurpers. The emperors also moved soldiers away from the Rhine and Danube frontiers so there was less protection and were more vulnerable to attacks. The wars lasted years and exhausted the Roman army. The borders were so depleted with soldiers that Rhine was dependent on the loyalty of local barbarian kings for defense which they were also trying to keep out at the same time. In the end, the emperors and rebels died at the hands of their own associates.
To gain more security, large provinces were split into smaller regions to minimize military power to any one official so one administrator doesn't have significantly more power than another. As provinces continue to be broken up, the army for each area became so small they could not even protect the locals from raids and criminals. A successful usurper named Constantine changed the composition of the Roman army and crippled the empire's central government by abandoning Rome as a capital, along with other emperors, with slow, ineffective communication between the officials and uncertainty at the court which made it hard to operate the government. He tried to avoid conflict and did nothing to...