Megalópoli - Thersileion

Immediately north of the theater at Megalópolis is the Thersileion (so named after the donor), a huge rectangular hall measuring 66m/217ft by 52m/171ft in which Arcadian federal assembly met. The interior probably had the form of an odeion, with radially disposed Doric columns supporting the roof. On either side of the Thersileion were altars. To the west was the stadion, to the east a sanctuary of Asklepios.

On the far side of the river, opposite the Thersileion, was a large sanctuary of Zeus Soter, and beyond this the agora, bounded on the north by a stoa erected by Philip II of Macedon.