The League of Corinth was an initiative of King Philip II of Macedon to unite all Greek city-states against the Persians’ Achaemenid Empire.
Also known as the Hellenic League, and led by Philip himself, the idea of a confederation was proposed to the king of Macedon by Isocrates of Athens in 346 BC and was created in 337 BC.
The League of Corinth unified Greek military forces under Macedonian hegemony in their combined conquest of the Persian Achaemenid Empire.
The Persian forces and Athens
The Persian forces under Artaxerxes had advanced in Ionia and Lycia and regained control of the Aegean and the Mediterranean Sea, taking over much of Athens’ former island empire.
In response, Isocrates of Athens started giving speeches calling for a force — which would later become the League of Corinth — to stop the Persians, but no Greek city-state was strong enough to fight against Artaxerxes’ army.
At the same time, the growing power and territory of Philip II of Macedon made him the strongest possible opponent of the Persians.
Philip’s power did not pass unnoticed by Artaxerxes. The Persian emperor ordered that the Macedon king’s power and influence should be constrained.
In 340 BC, the Persian emperor ordered a force to assist the Thracian prince, Cersobleptes, to maintain his independence against the Macedonian king — who still conquered Thrace despite this.
The first council of the League
The title “League of Corinth” was invented by modern historians because the first council of the League took place in Ancient Corinth.
The organization was the first time in history that the Greek city-states would unify under a single political entity.
The League was governed by the hegemon — King Philip II — and the Synedrion (council) of representatives of the participating city-states and the Dikastai (judges).
Sparta was the only city-state that refused to join because they were too proud to join under the hegemony of Macedon.
Decrees of the league were issued in Corinth, Athens, Delphi, Olympia and Pydna. The League maintained an army to which each state provided troops proportionately.
Philip established Hellenic garrisons in Corinth, Thebes, Pydna and Ambracia.
The representatives of the city-states made an oath of allegiance to the League of Corinth:
“I swear by Zeus, Gaia, Helios, Poseidon and all the gods and goddesses. I will abide by the common peace and I will neither break the agreement with Philip, nor take up arms on land or sea, harming any of those abiding by the oaths.
“Nor shall I take any city, or fortress, nor harbor by craft or contrivance, with intent of war against the participants of the war.
“Nor shall I depose the kingship of Philip or his descendants, nor the constitutions existing in each state, when they swore the oaths of the peace.
“Nor shall I do anything contrary to these agreements, nor shall I allow anyone else as far as possible.
“But if anyone does commit any breach of the treaty, I shall go in support as called by those who need and I shall fight the transgressors of the common peace, as decided (by the council) and called on by the hegemon and I shall not abandon…”
The oath continues with the names of the cities to be protected as members of the League, namely Thessaly, Elimiotis, Samothrace, Thasos, Ambracia, Phocis, Locris, Oetaea, Maliea, Ainis, Dolopia, Agraea, Perrhaebia, Zacynthus and Cephalonia.
The League under Alexander the Great
Philip never saw the great alliance in battle as he was murdered the following year (336 BC), with his son, Alexander the Great succeeding him as head of the League of Corinth.
Upon hearing a false report of Alexander’s death, Thebes — a very powerful city-state — revolted from the league and expelled the Macedonian garrison, breaking the oath.
In the previous century when the Persians had invaded Greece, Thebes had made an alliance with the invaders giving them earth and water, leaving the rest of the Greeks defending the land by themselves.
The alliance could not forgive the revolt of Thebes and the only action left was the war against Thebes. The decision for the destruction of the city was taken by the council of the League of Corinth by a large majority.
Alexander’s army acted swiftly and ransacked Thebes. Alexander spared the priests of the city and the house of poet Pindar.
The Thebans were condemned to slavery and its territory was distributed among neighboring states in 335 BC.
After that Alexander took over his father’s plan to invade Persia and with the League of Corinth joining the campaign by contributing to his army. Again, the Lacedaemonians (Spartans) abstained from the campaign in Asia.
Upon leaving, Alexander appointed general Antipater as deputy hegemon of the League of Corinth and recommended that the Athenians attended to its affairs and in case something happened to him, Athens would take over the power in Greece.
The League of Corinth is mentioned by Arrian after the victorious Battle of Granicus (334 BC). Alexander sent 300 panoplies to the temple of Pallas Athena in Athens, with the following inscription:
“Alexander, son of Philip, and the Hellenes, except the Lacedaemonians, from the barbarians inhabiting Asia.”
According to Diodorus Siculus, the League’s council sent a golden wreath to Alexander after the Battle of Issus.
After the Battle of Megalopolis in 331 BC, Sparta appealed to Alexander for terms, to which he agreed on condition that the Lacedaemonians now joined the League of Corinth.
In 323 BC, Alexander the Great died in Babylon. A year later, Antipater and his army fought the Lamian War against a coalition of Central Greece city-states, and after that the League was dissolved.