Battle of Issus
The Persians had put together a huge force, over 100,000 men with the Persian king Darius III personally among them to face Alexander's 30,000 men. Alexander adopted the tactics of Epaminondas that he used at the Battle of Leuctra, attacking one section of the Persian line in force. His plan worked beautifully as Macedonian cavalry assault smashed the Persian left, then wheeled westward into the exposed center of the Persian army. The Macedonian center had been involved in difficult combat, especially as they were crossing the river, but that changed when the cavalry arrived. Meanwhile a Persian attack against the Macedonian right was repulsed. As the Persian center gave way under the combined cavalry and infantry attack of Alexander's army, the Persian army started to flee in panic. Darius fled the field. Persian losses were more than 50,000 killed. Alexander lost 450 men. Among those captured were the family of Darius, including his queen, children, and mother.
Encyclopedia of Military History, Dupuy & Dupuy, 1979