The fall of the Roman Empire was a gradual process spanning several centuries, with different causes affecting the Western and Eastern halves. Here are the key factors:

## Political Instability
- **Crisis of leadership**: Frequent civil wars, assassinations, and short-lived emperors weakened central authority
- **Division of the empire** (285-395 CE): Split into Western and Eastern halves, diluting resources and coordination
- **Loss of civic virtue**: Decline in traditional Roman values and citizen participation

## Economic Decline
- **Debasement of currency**: Inflation caused by reducing silver content in coins
- **Heavy taxation**: Needed to fund the military and bureaucracy, but crippled productivity
- **Decline in trade**: Disrupted by constant warfare and barbarian raids
- **Loss of agricultural productivity**: Warfare and population decline affected food production

## Military Pressures
- **Barbarian migrations**: Germanic tribes, Huns, and others pressed against Roman borders
- **Overextension**: Empire became too large to defend effectively
- **Reliance on foreign mercenaries**: "Barbarization" of the army reduced loyalty and effectiveness
- **Military expenses**: Standing armies were extremely costly to maintain

## Social and Cultural Changes
- **Rise of Christianity**: Shifted focus from civic duty to spiritual concerns
- **Loss of Roman identity**: Increasing diversity diluted traditional Roman culture
- **Urban decline**: Cities shrank as people fled to the countryside for safety

## External Threats
- **Barbarian invasions**: Visigoths sacked Rome (410), Vandals followed (455)
- **Rise of new powers**: Sassanid Persia in the east, various Germanic kingdoms in the west

The Western Roman Empire officially ended in 476 CE, while the Eastern Empire (Byzantine Empire) continued for another thousand years until 1453 CE.
