Megalopolis

Megalopolis was a creation of the Arcadian League in the mid-4th century BC, through a synoecism of several settlements in the Peloponnese. This new polis was supposed to be the capital of the League. The number of settlements varies according to the ancient sources, but in any case Tegea, Mantinea, Kleitor, Mainalia and Parrhasia took part in this synoecism. These poleis are said to have come together in order to withstand Spartan pressure.
If the territory had been made up of all the communities listed in Paus. 8.27.3-4, it would have covered 1,500 km². However, if Moggi's reconstruction based on Diodorus is preferred, the territory would have covered about 400 km², somewhat larger than that of Tegea but smaller than that of Kleitor. (cf. Hansen, 2004: 521)
The material remains of the polis include a bouleuterion, a stoa, an agora with the temple dedicated to Zeus Soter, a theatre with seating for 20,000 people, and walls. Most date from the time of the foundation in the mid-4th century BC.
Archaeological surface survey indicates that, even though the inhabitants who took part in the synoecism settled in the ásty, there are many traces of habitation in the rural area, both in scattered farmsteads and in nucleated settlements.