Aetolian League
In the late 4th century BCE, the city was joined (synoecism) with the neighbouring cities of Phylace and Pyrasos. The new conurbation retained the name of Phthiotic or Thessalian Thebes, and became the main city of the Phthiotic Achaean League until it joined the Aetolian League in the late 3rd century BCE. Professor John Grainger of the University of Birmingham concluded, from evidence relating to the election of men from Thebes to office in the Aetolian League, that the city became a member of the League in the 220s BCE.