The fall of the Roman Empire was caused by a combination of internal and external factors. Internally, political instability, corruption, economic decline, and social unrest weakened the empire. Frequent changes in leadership and civil wars undermined government authority, while heavy taxation and reliance on slave labor contributed to economic stagnation. Externally, invasions by various barbarian tribes, such as the Visigoths and Vandals, put immense pressure on Roman borders. These factors culminated in the eventual collapse of the Western Roman Empire in 476 AD, marking the end of ancient Roman civilization and the beginning of the Middle Ages in Europe, profoundly influencing subsequent history.