Philip II of Macedon is assassinated at Aigai; Alexander (age 20) is proclaimed king, inheriting Macedonian hegemony in Greece and Philip’s planned war against Persia.
After a Theban revolt, Alexander’s forces defeat and raze Thebes, a punitive act meant to deter further uprisings in Greece before the Persian campaign.
Alexander crosses the Hellespont into Asia Minor, marking the opening of his major campaign against the Achaemenid Empire.
At the Granicus River, Alexander wins his first major battle in Asia (May 334 BCE), opening much of Asia Minor to Macedonian advance and weakening Persian control there.
Alexander besieges Halicarnassus (334 BCE), a key coastal stronghold; its fall helps secure southwestern Asia Minor despite Persian naval pressure.
Alexander defeats King Darius III at Issus (5 November 333 BCE), forcing Darius to flee and enabling Alexander to push into the eastern Mediterranean while capturing the Persian royal family and treasure.
Alexander founds Alexandria on Egypt’s Mediterranean coast (traditionally dated to 332 BCE), creating a strategic port and future Hellenistic cultural center.
After a protracted siege (January–July 332 BCE), Alexander captures the island-city of Tyre, securing key Phoenician ports and further undermining Persian maritime power in the region.
At Gaugamela (1 October 331 BCE), Alexander decisively defeats Darius III, effectively determining the fate of the Achaemenid Empire and opening the way to major imperial capitals.
In 330 BCE, Alexander takes Persepolis, a ceremonial capital of the Achaemenids; parts of the palace complex are burned, a symbolic and politically charged act in the aftermath of conquest.
As Alexander advances east, Darius III is deposed by his own nobles and killed in July 330 BCE, removing the last Achaemenid king and shifting the war into pursuits and consolidation across the former empire.
Alexander defeats King Porus at the Hydaspes (326 BCE), his last major pitched battle; the victory marks the farthest extent of his advance into the Indian subcontinent before his army forces a return.
At Susa in 324 BCE (noted in sources as February 324), Alexander organizes mass marriages between Macedonian officers and Persian noblewomen, aiming to bind ruling elites across his empire.
At Opis in 324 BCE (placed by Arrian’s narrative in August 324), Macedonian troops mutiny amid tensions over demobilization and Alexander’s perceived “orientalizing” policies; the crisis is suppressed and followed by reconciliation.
After falling ill in Babylon, Alexander dies on 13 June 323 BCE, triggering succession crises and the eventual fragmentation of his empire among rival successors (the Diadochi).
Alexander the Great's Campaigns and the End of the Classical Era (336–323 BCE)
