Aristotle was Alexander’s tutor. He gave Alexander thorough training in rhetoric and literature and stimulated his interest in science, medicine, and philosophy. In the summer of 336 BC, Philip was assassinated, and Alexander ascended to the Macedonian throne. He found himself surrounded by enemies at home and threatened by rebellion abroad. However, he disposed off quickly all conspirators and domestic enemies by ordering their execution.
Then, he descended on Thessaly, where partisans of independence had gained ascendancy, and restored Macedonian rule. Before the end of the summer of 336 BC, he had reestablished his position in Greece and was elected by a congress of states at Corinth. In 335 BC, as general of die Greeks in a campaign against the Persians, originally planned by his father, he carried out a successful campaign against the defecting Thracians, penetrating to the Danube River. On his return, he crushed in a single week the threatening Illyrians and then hastened to Thebes, which had revolted.
He took the city by storm and razed it, sparing only the temples of the gods and the house of the Greek lyric poet Pindar, and selling the surviving inhabitants, about 8000 in number, into slavery. Alexander’s promptness in crushing the revolt of Thebes brought the other Greek states into instant and abject submission. He began his war against Persia in the spring of 334 BC by crossing the Hellespont (modern Dardanelles) with an army of 35,000 Macedonian and Greek troops; his chief officers, all Macedonians, included Antigonus, Ptolemy, and Seleucus. At the river Granicus, near the ancient city of Troy, he attacked an army of Persians and Greek hoplites (mercenaries) totaling 40,000 men. His forces defeated the enemy and, according to tradition, lost only 110 men; after this battle all the states of Asia Minor submitted to him.
In passing through Phrygia, he is said to have cut with his sword the Gordian knot. Continuing to advance southward, Alexander encountered the main Persian army, commanded by King Darius III, at Issus, in northeastern Syria. The size of Darius’s army is unknown; the ancient tradition that it contained 500,000 men is now considered a fantastic exaggeration. The Battle of Issus, in 333 BC, ended in a great victory for Alexander. Cut off from his base, Darius fled northward, abandoning his mother, wife, and children to Alexander, who treated them with the respect due to royalty. Tyre, a strongly fortified seaport, offered obstinate resistance, but Alexander took it by storm in 332 BC after a siege of seven months.
Alexander captured Gaza next and then passed on into Egypt, where he was greeted as a deliverer. By these successes he secured control of the entire eastern Mediterranean coastline. Later in 332 BC he founded, at the mouth of the Nile River, the city of Alexandria. The great ruler died of high fever in 323 BC, just one month short of attaining 33 years of age.