Ancient city, central Peloponnese, Greece.
Occupying both banks of the Helisson River, it was founded in 371–368 BC by Epaminondas of Thebes as the seat of the Arcadian League . Attacked several times by Sparta , it joined the Achaean League in 234 BC. It declined rapidly after being plundered by Cleomenes III of Sparta in 223 BC, and by the 2nd century AD it lay in ruins. The nearby modern town lies in a rich lignite-bearing region that fuels thermal power stations.