Why did Alexander win at Arbela?

Alexander the Great won the Battle of Gaugamela, often called the Battle of Arbela, for several reasons. Gaugamela was a decisive battle fought on October 1, 331 BCE between the Hellenic League led by Alexander the Great and the Persian Empire of Darius III. Here are the reasons for his victory:

1. Superior Tactics: Alexander was an extremely skilled tactician. He used the phalanx formation, which was an arrangement of soldiers standing side by side in ranks with long spears called sarissas. This formation was very effective against the more loosely organized Persian forces.

2. Cavalry Use: Alexander was also masterful in his use of cavalry. His Companion cavalry was heavily trained and could perform complex maneuvers. He used them to exploit weaknesses in the Persian lines, including breaking through at critical moments.

3. The Hammer and Anvil Strategy: The Macedonian army under Alexander often utilized the "hammer and anvil" strategy. The phalanxes would engage the enemy (acting as the anvil), holding them in place, while Alexander's cavalry (the hammer) would strike the decisive blow.

4. Psychological Warfare: Alexander was adept at using psychological tactics to unnerve his opponents. He employed shock tactics, sudden charges, and feints that confused the Persian army.

5. Weaknesses in the Persian Army: The Persian army was vast, but it was not as disciplined or as well trained as Alexander's forces. Alexander's smaller, more professional army could react more quickly and cohesively.

6. Leadership: Alexander's personal bravery and leadership inspired his troops to fight with great fervor. Darius III, in contrast, failed to inspire his own troops and fled from the battlefield, demoralizing his soldiers.

Due to these factors, and perhaps a degree of luck or destiny as some ancient sources might suggest, Alexander won the Battle of Gaugamela in a decisive manner, ensuring his control over the Persian Empire.