By first capturing the sea coast of the Eastern Mediterranean to deprive the Persian navies of their ports and so their ability to attack the Greek cities by sea.
By reducing the Persian ability to enlist Greek mercenary armoured infantry to augment the Persian armies by executing those captured after the battle of Grannicus as a warning to them.
By assembling a mercenary cavalry arm to match the Persian cavalry, giving himself a superior combination of power and manoeuvre.
Gaugamela.
I'm almost positive that he defeated the Persians at the Battle of Gaugamela.
Alexander the Great decisively defeated the Persians led by Darius the Third at Gaugamela (located in Iraq) October 1, 331 BC .
Alexander the Great defeated Darius, king of Persia in 331 BCE. This was at the battle Gaugamela, he did march through Bactria in 329 BCE, but he had already defeated the Persians.
when he defeat the king darius 3
There were several. The most decisive was Gaugamela.
Alexander the great
Alexander the Great.
Alexander the Great .
Gaugamela.
Alexander the Great lead the Greeks to defeat the Persians. After doing so, Alexander conquered many other lands and created the largest empire the world has ever seen at the time. He built many cities named after himself (Alexandria), but the most well-known Alexandria was in Egypt where he built a lighthouse 394 feet tall (120 meters). Alexander was one of the greatest conquerors in history.
Cyrus the Great