Mantinea, one of the oldest and most powerful towns of Arcadia, on the borders of Ar-golis and the river Ophis. Its democratic political constitution was, according to Polybius, one of the best in antiquity. Like the other Arcadian towns, it acknowledged the Spartan supremacy prior to and during the Persian war.
It was an ally of Sparta in the earlv part of the IMoponnesian war, but in 421-20 B. 0. formed a confederacy with Argos, Elis, and Athens, which was defeated and dissolved by the Lace-dternomans in 418. Though it became again an ally of Sparta, its increasing power rendered it obnoxious to the latter city, and in 385 the Spartans attacked and destroyed it by turning the waters of the Ophis against its walls. The. Mantineans rebuilt their city after the overthrow of the Spartan supremacy bv the battle of Leuctxa in 371. They were prominent in the formation of the Arcadian confederacy, but soon abandoned it for an alliance with their ancient enemies the Spartans, To prevent this coalition Epaminondas marched into the Peloponnesus, and Mantinea is chiefly celebrated as the scene of the great battle (362) between the Thebans and Spartans, in which he fell. It continued one of the most important towns of Arcadia till the time of the Achcean league, which it at first joined, but subsequently deserted for the Aetolian confederacy, an event which occasioned the Cleo-menic war.
In 226 it was surprised and terribly chastised by Aratus, and in 222 it was plundered by Antigonus Doson, and its name changed to Antigonea, which it bore till its ancient appellation was restored by the emperor Hadrian. The ruins of Mantinea are visible at the modern village of Paleopoli, in a bare plain, 8 m. N. of Tripolitza; they consist of the remains of the theatre and three courses of masonry of the entire circuit of the walls, which were elliptical, 1,250 yards in diameter, with 10 gates and 118 towers.