The war between the Greek city states and Macedonia became inevitable when, in 340, king Philip of Macedonia was besieging Perinthus - on the west bank of the Sea of Marmara - and the Macedonians captured a food convoy headed for Athens. Immediately, Athens declared war and started a blockade of the Macedonian ports. Philip, who had already discovered that Perinthus received supplies from the Persian Empire, and found himself fighting against Persian armies in Europe, broke off the siege, and decided to invade Greece. He spent some time in Macedonia, and then, unexpectedly, moved to the south, at lightning speed. The Greek allies found it impossible to block the road at Thermopylae, and met the Macedonians at Chaeronea, along the road from Thermopylae to Thebes. It was August 338.
According to Polyaenus, the Macedonians used a stratagem:
After drawing up his formation against the Athenians at Chaeronea, Philip yielded and gave way. An Athenian general, Stratocles, shouted "We must not stop pressing them until we shut the enemy in Macedonia," and he did not give up the pursuit. Philip, saying "The Athenians do not understand how to win," retreated gradually, keeping his phalanx drawn together and protected by shields. A little later, gaining some high ground, encouraging his troops, and turning around, he attacked the Athenians vigorously and, fighting brilliantly, he conquered.note[Polyaenus, Stratagems 2.2.2; tr. P. Krentz & E.K. Wheeler.]
A different story is told by Diodorus of Sicily:
The armies deployed at dawn, and the king stationed his son Alexander, young in age but noted for his valor and swiftness of action, on one wing, placing beside him his most seasoned generals, while he himself at the head of picked men exercised the command over the other; individual units were stationed where the occasion required. On the other side, dividing the line according to nationality, the Athenians assigned one wing to the Boeotians and kept command of the other themselves. Once joined, the battle was hotly contested for a long time and many fell on both sides, so that for a while the struggle permitted hopes of victory to both.
Then Alexander, his heart set on showing his father his prowess and yielding to none in will to win, ably seconded by his men, first succeeded in rupturing the solid front of the enemy line and striking down many he bore heavily on the troops opposite him. As the same success was son by his companions, gaps in the front were constantly opened. Corpses piled up, until finally Alexander forced his way through the line and put his opponents to flight. Then the king also in person advanced, well in front not conceding credit for the victory even to Alexander; he efficient forced back the troops stationed before him and then by compelling them to flee became the man responsible for the victory.
More than a thousand Athenians fell in the battle and no less than two thousand were captured. Likewise, many of the Boeotians were killed and not a few taken prisoners. After the battle Philip raised a trophy of victory, yielded the dead for burial, gave sacrifices to the gods for victory, and rewarded according to their deserts those of his men who had distinguished themselves.note[Diodorus of Sicily, World History 16.86; tr. C. Bradford Welles.]
It is possible to harmonize these accounts. It seems that the right wing of the Macedonian army slowly moved backwards, and that the Athenians (on the Greek left wing) moved forwards. This created a gap in the Greek lines; the Athenians lost contact with the Thebans on the Greek right wing. When this gap opened, Alexander, who commanded the Macedonian left, charged and broke through. He attacked the Greek right wing, which was occupied by the famous "Sacred Band" of Thebans, which was massacred. This was the end of the battle - and the beginning of the spectacular military career of Alexander.
After the battle, Philip reorganized Greece. On several places (Corinth, Thebes...) he laid garrisons, and he proceeded to Sparta, to show the power of his weapons on the Peloponnese as well. This action was broken off when news arrived that in the Persian Empire, king Artaxerxes III Ochus had died. Because a new Achaemenid king would need some time to establish his power, the Macedonians had a golden opportunity to invade Asia. Therefore, Philip forced the once independent cities to conclude a common peace and become members of the Corinthian League (text), which declared war against the Persian Empire. The Macedonian army would be enlarged by regiments of the Greek allies, which would - of course - also serve as hostages.
Alexander was now about eighteen years old, and had already been portrayed on Macedonian coins. Philip now gave him even more "visibility" by erecting a group of statues, in which he himself was shown as charioteer, Alexander standing next to him (the "Rondanini Alexander"). This turned out to be a clever move, because Philip was assassinated before he could join the Persian war, and Alexander had already been recognized by almost everyone as Philip's successor, especially now that he had proved himself to be a superior warrior.
It must be remarked that the importance of the battle has been overestimated. It is often said that the significance of "Chaeronea" was that the freedom of the Greek cities came to an end. However, the Third Sacred War (354-346) had probably done the real political damage.
Writing several centuries after the battle, Greek writer Pausanias noted that
near the city of Chaeronea is the communal grave of the Thebans who were killed in action. It contains no epitaph, there is just a statue of a lion, which was perhaps chosen to commemorate the courage of the men. The absence of an inscription is, in my view, because their courage was not rewarded with good fortune.note[Pausanias, Guide to Greece 9.40.4.]
The remains of the statue have been found and the monument has been restored.