What was a primary factor leading to the end of the Roman Empire?

The primary factor leading to the end of the Roman Empire was the external invasions by barbarian tribes. During the late Roman Empire, various groups, such as the Visigoths, Vandals, and Huns, began migrating into Roman territories. These invasions were not merely occasional raids; they often involved significant and organized military campaigns that challenged the stability and security of the Empire.

The conquest of key territories, including Rome itself in 410 AD by the Visigoths, highlighted the Empire's weakened defenses and its inability to protect its borders. This constant state of pressure from external forces contributed to the fragmentation of the Empire and ultimately its fall in the West in 476 AD.

The other factors, such as increased trade with Asia, contributed to economic enhancements and cultural exchanges but did not directly lead to the empire's collapse. The spread of Christianity influenced societal aspects and governance but did not act as a direct cause for the Empire's downfall. Corruption in government certainly weakened the internal structures of the Empire, yet the immediate existential threat from external invasions was a more decisive factor in its end.