The fall of the Western Roman Empire (traditionally dated to **476 AD**) was not caused by a single cataclysmic event. Instead, it was the result of a "perfect storm" of internal decay and external pressures that accumulated over several centuries.

Historians generally categorize these causes into five main areas:

### 1. Barbarian Invasions and Military Decline
For centuries, Rome struggled with Germanic tribes. However, by the 300s, groups like the Goths, Vandals, and Huns were pushing deeper into Roman territory.
*   **The Sack of Rome:** In 410 AD, the Visigoths (led by Alaric) sacked Rome for the first time in 800 years. In 455 AD, the Vandals sacked it again.
*   **The "Germanization" of the Army:** To fill its ranks, Rome began hiring foreign mercenaries (foederati). These soldiers had little loyalty to the Empire and were often more loyal to their individual commanders, leading to internal instability and coups.

### 2. Economic Crisis and Overexpansion
The Roman economy was built on conquest and slave labor. When the Empire stopped expanding, its primary sources of wealth and labor dried up.
*   **Inflation:** To pay for the massive military, emperors began "degrading" the currency (mixing gold and silver with cheaper metals). This caused hyperinflation, making trade difficult.
*   **Labor Shortage:** As expansion stopped, the supply of slaves dwindled, leading to a collapse in agricultural productivity.
*   **Heavy Taxation:** To keep the government running, the state placed an immense tax burden on the middle class and farmers, many of whom fled their land to avoid paying.

### 3. Political Instability and Corruption
The Roman system of government never established a clear, reliable method for choosing a new emperor.
*   **The Praetorian Guard:** The Emperor's own bodyguards frequently assassinated leaders and "auctioned" the throne to the highest bidder.
*   **Civil Wars:** During the "Crisis of the Third Century," scores of emperors rose and fell in quick succession, with many being assassinated by their own troops. This internal chaos left the borders undefended.

### 4. The Division of the Empire
In 285 AD, Emperor Diocletian divided the Empire into two halves: the **Western Empire** (Milan/Ravenna) and the **Eastern Empire** (Byzantium/Constantinople).
*   **Resource Disparity:** The East was wealthier, more populous, and easier to defend. The West, however, was poorer and bore the brunt of barbarian attacks.
*   **Failure to Cooperate:** The two halves often argued over resources and military aid. When the Western Empire began to collapse, the Eastern Empire (which survived as the **Byzantine Empire**) often left the West to fend for itself.

### 5. Social and Religious Changes
Early Rome was built on *virtus* (civic virtue) and loyalty to the state. Over time, this social fabric frayed.
*   **Christianity:** Some historians, most notably Edward Gibbon, argued that Christianity’s focus on the afterlife and pacifism weakened the traditional Roman martial spirit. (Modern historians debate this, noting that Christianity also provided a unifying social structure).
*   **Loss of Civic Pride:** Wealthy elites increasingly avoided public service and retreated to their private estates, leaving the management of cities to crumble.

### The "Final Blow"
In **476 AD**, the Germanic leader **Odoacer** revolted and deposed the young emperor Romulus Augustulus. Unlike previous usurpers, Odoacer did not appoint a puppet Roman emperor; he declared himself King of Italy. While the Eastern Empire continued for another thousand years, the Western Empire had ceased to exist as a unified political entity.
