Greek Macedon Chalkidian League - Olynthos

The growing influence and expansionist aims of the Chalkidian League led by Olynthos had in 382 BC led to calls from Amyntas of Macedon, as well as Akanthos and Apollonia [who anticipated imminent conquest by the League], for Spartan intervention to check the League's power. Sparta, keen to reassert its presence in northern Greece, consented and a force of 10,000 was mobilised and dispatched against the League. After several years of protracted but indecisive warfare, Olynthos agreed to dissolve the Chalkidian League, though this dissolution appears to have been little more than a token formality, since in the following year the League appears among the members of the Athenian naval confederacy, and twenty years later Demosthenes reported the power of the League as being much greater than before the Spartan expedition. Olynthos itself is at this time spoken of as a city of the first rank, and the Chalkidian League then comprised thirty-two cities.

Olynthos was allied with Macedon when Philip II and Athens went to war in 356 after Philip's capture of the Athenian colonies of Pydna and Potidea. Around this time Philip II also allowed himself to be drawn into the Sacred War on behalf of the Thessalians; since Athens was also a combatant in the Sacred War, the war between Athens and Macedon became inextricably linked with the progress of the Sacred War.

Alarmed by Philip's aggressive policies and further invasions of neighbouring territories, Olynthos concluded an alliance with Athens in 352. The city made three embassies to Athens, the occasions of Demosthenes's three Olynthiac Orations. On the third, the Athenians sent soldiers from among its citizens to garrison the city and reinforce its defences. In response Philip II attacked the Chalkidian League in 349, and by 348, he had completely destroyed the League, razing Olynthos to the ground in the process.