The fall of the Roman Empire and Abbasids was due to a combination of internal and external factors such as ineffective governance, economic systems, foreign invasions, and societal issues.
Although the Roman Empire and the Abbasid Empire encountered comparable issues, their outcomes differed. Political instability and a capital relocation weakened Rome's army and population, whereas governance and succession problems led to focus on managing slave revolts and assassination attempts in Abbasid. Mogul invaders captured Baghdad as the military couldn't defend against them. Both empires suffered from internal factors such as political and economic turmoil contributing to their declines. In addition, weak leadership patterns and military involvement in selecting future rulers contributed to Rome's downfall.
Despite differences in the way it occurred, the Abbasid Empire also faced a succession issue. The government's decision to
...establish new capitals incurred further costs to the already depleted funds of the empire, which were drained by the caliphs' desire for luxury and building. Consequently, the government turned to the people for more money, leading to an exodus of people from many areas of the empire. Neither empire's military was equipped to protect against invaders. In Rome's case, hiring troops added more debt to their already considerable financial woes.
Both the Roman and Abbasid empires experienced a decline in power and influence, with internal failures contributing to their respective downfalls. The Roman empire was conquered by Germanic invasions that were easily successful due to weakened defenses caused by internal issues. Similarly, the Abbasid military struggled with protecting itself from attacks by the Buyids from Persia, as the government proved incapable of defending against them. A declining population also played a role in the fall
of both empires; for example, uncontrollable disease decimated Rome's population from one million to 250,000. This dwindling population did not resist invasions because they believed that it was not worth protecting an already deteriorating empire.
Abandoning villages, facing hardships from excessive government spending and higher taxes, the population played a role in the decline of the Abbasid Empire. Peasants died from floods, famine, and violent attacks even in wealthy regions. The Shi’ia community attempted to rebel against Abbasid rule by trying to overthrow it entirely.
