Alexander was only 20 years old when he ruled Macedonia and Greece. Since he was 16 he already became a commander of the Macedonian Army.
In the year 334 B.C he led the 30,000 Greek soldiers with 5,000 cavalry into Asia and campaigns to conquer the East dominated by the Persian Empire.
His first fight with the Persians was in the Granicus River West of Asia Minor. As he won the battle he sends 300 suits of Persian armor to Greece to offer it to Athena.
The second battle was happened on 333 B.C in Issus, Syria. Alexander became victorious, Darius III, the
king of Persia forced to flee.Alexander then captured the seaport of Phoenicia and cut the supply of the Persian fleets. The Persian fleet forced to surrender.
Alexander then invaded Egypt that was on that time controlled by Persia. The people of Egypt discontented of the Persian rule welcomed Alexander and declared him as Pharaoh.
Alexander build a new city in Egypt and named it Alexandria after himself.In 331 B.C, he invaded Mesopotamia destroying the Persians main army in Gaugamela near the Tigris River. He was able to capture the key cities of Persian empire; Babylon, Persepolis, and Susa.
After Darius III was killed by one of his general, Alexander declared himself the king of the kings and ruler of Persian Empire.
In 327 B.C, He lead his entire soldier to India and reached the Indus valley after 3 years. He hoped to go farther but his soldier refuse because they were already very far.
Alexander turned and went to Babylon and made it the capital of his empire. He fell ill with a fever,probably cause by a Malaria and died in 323 B.C at the age of 33.