Aetolia is a mountainous region of ancient Greece on the north coast of the Gulf of Corinth.
The river Achelous separates Aetolia from Acarnania to the west; on the north it had boundaries with Epirus and Thessaly; on the east with the Ozolian Locrians; and on the south the entrance to the Corinthian Gulf defined the limits of Aetolia.
In classical times Aetolia comprised two parts: Old Aetolia in the west, from the Achelous to the Evenus and Calydon; and New Aetolia or Acquired Aetolia in the east, from the Evenus and Calydon to the Ozolian Locrians. The country has a level and fruitful coastal region, but an unproductive and mountainous interior. The mountains contained many wild beasts, and acquired fame in Greek mythology as the scene of the hunt for the Calydonian Boar.
The peoples known as the Curetes and the Leleges originally inhabited the country, but at an early period Greeks from Elis, led by the mythical Aetolus, set up colonies. The Aetolians took part in the Trojan War, under their king Thoas.
The Aetolians set up a united league in early times, it soon became a powerful military confederation, it had originally been organized during the reign of Philip II by the cities of Aetolia for their mutual benefit and protection, and became a formidable rival to the Macedonian monarchs and the Achaean League. The League was one of the more effective political institutions that was produced in its time.
Unlike Achaea, there was a division between full members of the League and allies over which Aetolia maintained a hegemony. This did however allow Aetolia to maintain a much more genuine democracy and the bi-annual meetings of the League assembly coincided with games so that a far higher proportion of the citizens would have attended in person. The Aetolians took the side of Antiochus III against the Roman Republic, and on the defeat of that monarch in 189 BC, they became virtually the subjects of Rome. Following the conquest of the Achaeans by Mummius in 146 BC, Aetolia became part of the Roman province of Achaea.
Aetolia's reputation has suffered from a rather hostile treatment in the sources. Polybius is considered now to have a heavy anti Aetolian bias due to him having relied on Aetolia's opponent Aratus of Achaea.
During the Middle Ages, Aetolia was part of the Byzantine Empire and later passed to the Turks: after a relatively unsuccessful attempt at colonization they took a token amount of slaves and resources from the region, then departed. Aetolia became part of Greece after the Greek Revolution of 1821. Today Aetolia is the eastern part of the Central Greece prefecture of Aitoloakarnania.
(This article incorporates material from Harry Thurston Peck's Harper's Dictionary of Classical Antiquities (1898).)