The castle is built on a low hill, at the southwest slopes of mount Parnon, near the village of Geraki. It was founded in 1209 by the Frankish baron Guy de Nivelet and remained under Frankish occupation until 1259. After the Franks were defeated in the battle of Pelagonia in 1259, the castle was given over to the Greeks in 1262 and supported the Despotate of Mystras (1262-1460).

The church of St. George and remains of urban buildings are preserved inside the castle, while ruins of buildings and churches have survived outside the fortified area. At the end of the 17th century the castle was captured by the Venetians, in 1715 was occupied by the Turks, and was finally abandoned at the end of the 18th century.

For many years the 5th Ephorate of Byzantine Antiquities has been conducting restoration work on the monuments of Geraki. Work has been almost completed for the churches and is currently progressing on the fortification walls and the secular buildings. The wall paintings of the churches have also been restored.

A large Early Christian basilica was excavated by A. Xyngopoulos in the outskirts of the village of Geraki, to the SW of the church of St. Athanassios. The apse of a second Early Christian basilica has been located under the apse of the church of Saint Sozon.