Wars of Alexander the Great

The wars of Alexander the Great were a series of campaigns fought between 336 and 323 BCE, in which the young king of Macedon conquered the Persian Achaemenid Empire and pushed on as far as the Indus valley. In little more than a decade he created the largest empire the ancient world had yet seen, stretching from Greece and Egypt to Central Asia and the Punjab. It did not survive him as a single state, but it spread Greek language and culture across the Near East.

Alexander's father, Philip II of Macedon, had made Macedon the leading power in Greece and organised most of the Greek city-states into an alliance, the League of Corinth, in preparation for a war against Persia. When Philip was assassinated in 336 BCE, Alexander, then twenty, took the throne. He first secured his northern frontiers with campaigns in the Balkans, then crushed a revolt by Thebes in 335 BCE, destroying the city as a warning to the other Greeks.

In 334 BCE Alexander crossed the Hellespont into Asia with a Macedonian and allied Greek army. He defeated the local Persian commanders at the Granicus River and took over the Greek cities of western Asia Minor. In 333 BCE he met King Darius III for the first time at Issus, in the corner between Anatolia and Syria, and routed him. Instead of pursuing Darius, he turned south to take the Phoenician ports and deny the Persian fleet its bases. Tyre resisted a long and difficult siege before falling in 332 BCE, and Gaza also had to be besieged.

Egypt, under Persian rule, surrendered without a fight. Alexander founded Alexandria on the Mediterranean coast and visited the oracle of Ammon at Siwa, in the western desert. In 331 BCE he marched into Mesopotamia and won his decisive victory over Darius at Gaugamela. The Persian capitals of Babylon, Susa and Persepolis fell to him, and in 330 BCE Darius was killed by his own officers while in flight.

The conquest of the eastern provinces proved far harder than the great battles in the west. Between 329 and 327 BCE Alexander fought a long and costly guerrilla war in Bactria and Sogdiana, roughly today's Afghanistan, Uzbekistan and Tajikistan. He married the Bactrian noblewoman Roxana, partly to reconcile the local aristocracy. Tensions grew in his own camp as he adopted Persian court customs, and several senior Macedonians were executed for alleged conspiracies.

In 326 BCE Alexander crossed into the Punjab and defeated the Indian king Porus at the Hydaspes River. When he reached the Hyphasis (the modern Beas), his exhausted troops refused to go any further, and he agreed to turn back. Part of the army returned by sea, and part followed Alexander through the Gedrosian desert in southern Iran, where many died of thirst and heat.

Alexander returned to Babylon and was planning further campaigns, possibly into Arabia, when he fell ill and died in June 323 BCE, aged thirty-two. He left no adult heir. His generals, known as the Diadochi or "successors", fought each other for decades, and the empire broke up into rival kingdoms, among them the Seleucid Empire in Asia and the Ptolemaic Kingdom in Egypt. These Hellenistic states carried Greek cities, language and administration across the region for the following three centuries.

Our 400 BCE map shows the Achaemenid Empire before the invasion, and the 323 BCE map shows the Macedonian Empire at Alexander's death. The 300 BCE map shows it already divided among his successors.