In 331 B.C. 23-year-old Alexander of Macedon advanced toward Persia. In the previous two years, he had conquered Egypt and the Mediterranean coast, then Syria, and now moved toward Persia to face the Persian emperor Darius. Alexander crossed the Tigris and Euphrates Rivers with his forces, while Darius mustered a large army. The two armies met and fought at Gaugamela, near the modern-day northern Iraqi city of Mosul. [The name Gaugamela comes from “gahmal”, or camel in Hebrew and Arabic, because supposedly the battle occurred near a camel-shaped hill.]

Alexander’s forces were vastly outnumbered. Some accounts say Darius’ army had a million soldiers. But the difficult logistics of feeding such an army suggest it was smaller, perhaps 100,000. However, Darius had 200 scythed chariots – chariots with fearful rotating knives on each side that could cut opposing soldiers and cavalry to pieces. Alexander had mustered a force less than half that of Darius, with no chariots.  

It appeared hopeless. But Alexander defeated Darius by several remarkable innovations. Here are just two of them:
 
•  The box or “mouse trap”: After Gaugamela, scythed chariots were never used again in battle. Alexander found a simple solution. He arranged his soldiers, carrying six-meter-long spears known as sarissa, into three-sided boxes, with spears facing inward. The Persian chariots rode into the mouse-trap box – and the horse pulling the chariot bolted and stopped when facing the spears ahead of it. It was then a simple matter for the Macedonians to annihilate the stationary chariot rider and his steed.
 
•  The tactics: Darius lined his forces up conventionally, with scythed chariots in front, then infantry, in a long row, with cavalry on the flanks. Darius was in the center. But Alexander placed  his cavalry at 45 degree angles on the flanks. He led the cavalry on the right, while his general Parmenion led the cavalry on the left. At the start of the battle Alexander led his cavalry in a slow trot parallel to the Persian lines – for the Persians, a puzzling move. Then, suddenly, Alexander turned  left toward the Persians, forming his troops into a kind of arrowhead and driving right toward the center of the Persian lines, toward Darius and his Royal Guards. The Persians had expected a conventional frontal battle, with front lines of each force engaging each other. They were perplexed and confused by Alexander’s innovation. Darius fled in panic – and the battle for him was lost.

 •  The leadership: While Darius fled, abandoning his troops to save himself, Alexander behaved differently. Seeing Darius fleeing, he began to pursue him. But Alexander got a message from Parmenion, on the left flank, saying that Parmenion’s cavalry was about to be annihilated by the Persians. Alexander had a tough choice: Capture and kill Darius and win the Persian Empire, or rescue his embattled general and troops. Surely, the driven, ambitious young Alexander would chose the Empire. But no – he chose his men. He broke off the fight, and returned to rescue Parmenion and save his cavalry.

There is rarely a strong innovation story, without some element of leadership. By showing that his soldiers meant more to him than the Persian Empire, Alexander won their loyalty forever – and earned the title Alexander the Great. Darius was soon murdered by a rival, who then declared fealty to Alexander.  

Alexander the Innovator, in 12 years, conquered most of the world known to the ancient Greeks. His empire reached as far as the Punjab in India. He never lost a battle. He died at age 33 of malaria, West Nile fever, encephalitis or heavy drinking, or a combination of them.