Battle of Chaeronea (338 BC)

In 348 BC, King Philip II of Macedonia occupied the strategically important city of Olynthos after a year-long siege. For the naval power Athens, the vital supply of grain from the Bosporan Empire seemed increasingly threatened by the Macedonian conquests. When Philip again fought the Thracian king Kersebleptes in 342 B.C., Athens again equipped a fleet to come to the aid of the cities of Perinthos and Byzantion, which were besieged by Philip's troops. Philip therefore had to leave both cities without having achieved anything.

In March 339 B.C. the Ozolic Lokrians of Amphissa had unlawfully cultivated land area of the sanctuary of Delphi, whereupon the Athenian orator Aeschines, the leader of the Macedonian party, induced the council of the Amphictyons to the Fourth Holy War. The first attack of the Lokrians having been repulsed, the Amphictyons, in October 339 B.C., elected the Macedonian king their new patron. Philip II was therefore given the necessary pretext, as he had been in the Third Holy War, to enter central Greece again with his troops. Since the Peace of Philocrates, he had also secured the passages at Thermopylae. The Macedonian troops ended the war against Amphissa victoriously, then, with the acquiescence of the Phocians, also occupied the city of Elateia on the Kephissos, a key point for the access routes to Boeotia and Attica. This imminent threat prompted the city of Thebes, which had hitherto maintained a steady relationship with Philip, to request Athens' assistance.

The persuasive speeches of the Athenian orator and politician Demosthenes, who hastened to Thebes, induced the city to abandon its old grudges and ally itself with its former adversary. The Athenian army had already pre-emptively entered Boeotia under Chares, and within a few days was able to unite with the Theban contingent under Theagenes. The allied army of both cities was also reinforced by small contingents from Chalcis, Megara, Achaia and Corinth. In August 338 BC, Philip's troops marched up the main road from Phocis to Boeotia to attack the allied army that had blocked the road at Chaironeia.

The Macedonian army, which like the Greek numbered about 30,000 men, was led by Philip II. His son Alexander made his first appearance and commanded the mounted troops on the left wing of the army. The alliance of the Greek poleis was largely due to Demosthenes' efforts (→ Philippika) and, according to estimates, comprised about 10,000 (albeit inexperienced) Athenian hoplites on the left wing, the allies and mercenaries in the middle of the formation, and, as the main force, the Theban troops, including the famous Sacred Host (300 elite soldiers), on the outer right wing.

The Athenians and allies proceeded in a rather disorganized manner at the beginning of the battle, while the Macedonian phalanx had withdrawn in an orderly fashion, only appearing to do so. The Theban force initially held formation while the Athenians moved to the left, opening a gap in the anti-Macedonian force. Into this gap Alexander now thrust his mounted force from the Macedonian left wing to devastating effect. Subsequently, the dreaded Macedonian phalanx advanced again. In the process, some parts of the Greek army broke away or fled, but the Theban Sacred Host held its ground, losing about 250 of its 300 men. Thus the defeat was devastating. The Athenian and Theban troops lost a total of about 2000 men and about 4000 hoplites were taken prisoner. The Macedonians suffered relatively few casualties; it was Alexander's first major victory, but he does not seem to have been decorated for it by Philip.