The abandoned castle of Agios Vassilios sits on an altitude of 580 meters, south of the Dafnia mountain and 1 kilometre north of the village Agios Vassilios. The castle used to measure 225 by 130 meters and have six towers equipped with battlements, the ruins of which still survive. Ruins of houses also survive, as well as parts of the wall which was built by the Franks before 1250.
The castle used to be the centre of the area, and in the beginning of the 15th century, the Palaiologos dynasty of the Despotate of the Morea had control of it. In 1460, the Turks conquered the castle and destroyed the fortifications, and in 1463 control passes to the Venetians, for a few years. In 1471, the venetian catalogues mention that the castle is destroyed.
It was finally abandoned in the 19th century.