Ancient Cleitor was one of the largest and richest ancient cities of the time. It was founded by Cleitoras, son of King Azana and grandson of Arcadian, the Archaic chieftain of the Arcadians. Many of its ruins (such as the ancient theatre) can be found scattered across the great plain of Cletoria. The theatre of Ancient Cleitoras has been excavated relatively recently, with investigations having brought to the surface the theatre's cave and some of the seats. There, in the courtyard of the theatre, theatrical performances are presented during the summer months.

Ancient Kleitor, a town in north-west Arcadia, known as Azania in antiquity, is located about 3 km west of Kato Klitoria and south of Ano. Its name probably owes its name to its enclosed position. According to the myths, it was founded by Klitora, the son of Azanos, who was the progenitor of the Arcadian tribe of Azans. Pausanias is the most important historical source for the topography, monuments and myths of the region, but the testimony of earlier sources such as Pindar, Xenophon, Plutarch, Polybius and Livy is also remarkable and enlightening. Many foreign travellers, Curtius, Dodwell, Leake, Frazer, Lebas, Bursian, Vischer and others, as well as the Greek historian C. Papandreou, visited the city and, based on the ancient sources and ruins, formulated their views on the monumental topography.

The fortification enclosure is estimated to have surrounded the city for a total length of about 3000 m., defining its area at about 577 hectares. The stone rampart of the wall is built according to the complex technique using the trapezoidal system. The superstructure of the stone wall was made of adobe. Two phases of the Hellenistic period are marked on the southwestern gate and an earlier one is defined, but it is not yet possible to determine it sufficiently chronologically. The theatre is located to the southwest of the city and shows evidence of a diazomae.