Boeotian Association

This confederation was formed in the 6th century BC because of the threat to Boeotia from Thessaly. The members of the confederation were the cities of Thebes (about 2/5 of the area of Boeotia), Haliartos, Koroneia, Tanagra, Thespia and Akraifnia. Later, all the cities (Orchomenos and others) joined, with the exception of Plataea, which was allied with Athens. The alliance, however, was by no means a solid one, threatened either by internal feuds or by pressure from neighbouring rivals.

In late 379 and early 378 BC, Thebes broke free from Spartan rule and thus began a war with Sparta. Thebes re-established the Boeotian League, in which the city of Orchomenos was absent (it remained on the side of Sparta). When the battle of Leukter was won by Thebes, thus the Boeotian League, and thus weakened the power of Sparta, the city of Orchomenos decided to rejoin the League. In 364 BC. Thebes occupied Thessaly and then destroyed Orchomenos under the pretext of an anti-democratic conspiracy.

The leadership of Thebes ended with the death of Epameinondas at the Battle of Mantinea in 362 BC.