On the western slope of Gortsouli hill, in the area of ancient Mantineia, survives a temple built during the archaic period. Since it was uncovered, the temple enlightens us considerably about the history of Mantineia before the fifth century BC. The Gortsouli hill is being identified by modern researchers as the prehistoric acropolis of Mantineia, called Ptolis, which was mentioned in the works of the traveller and geographer Pausanias (8, 8, 4). During the Archaic years, Ptolis distinguished itself as the central sacred location for the people of Mantineia, who were still dwelling in large villages in the plain that surrounded the hill. The portable findings discovered during excavations and investigations on the hill indicate that the place was already inhabited at the Prehistoric era, though no traces of edifices have been located up to date. The systematic investigation of the temple showed that the place was used for open-air adoration, without any interruption, from the late eighth century BC to the sixth century BC. It is likely that any attempts to found the first ceremonial building at the area began in the second half of the seventh century, but construction works were interrupted following the sliding and collapse of the western foundations due to the abrupt bent at that particular location. The posterior temple was founded during the third quarter of the sixth century BC, near the original one, at a distance about 0.70m to the east, and remained in use until the third century BC.

In general, the two buildings present many similarities: they both belong to the category of archaic ?residences? and are distinguished by the significant prolongation of the axis oriented from north to south. In both cases, the entrances are located at the south side, which is a narrow one. The earlier temple is divided, as well as the later temple, into a prodomos (anteroom), a cella building (in Greek sek?s) and an adyton (enclosed sanctuary, not accessible to all), with internal dimensions of 14.60 x 4.65m. The foundations of the earlier temple were used to erect the posterior temple, with internal dimensions of 14.25 x 4.70m. The inferior parts of both buildings were made with layers of unrefined local lime slabs without any conjunctive material, while the superstructure was probably earthen. Some parts of the walls of the posterior temple are preserved up to 0.80m of height.

On the interior of the temple were discovered votive offerings of significance. The most precious group of offerings includes earthen figurines representing exclusively feminine figures, in an impressive variety of types. They are dated between the seventh and the early fifth century BC and point to the cult of the goddess Artemis in that location, in her quality of protector of vegetation and breeder of sheep herds. Among the figurines one distinguishes imposing veil-bearers of significant height; it is the first time that such a type of figurines occurs in the sanctuary lying on the western slope. Also noteworthy among the excavation findings is an ensemble of iron pins, unparalleled in volume and state of preservation, recalling as to the typology the bronze pins that were also found in abundance within the temple. Several characteristic examples of the aforementioned votive offerings are today exposed in the Archaeological Museum of Tripolis.

The temple was uncovered during a rescue excavation, conducted in 1962 by the then Curator of Antiquities at the Fifth Ephorate for Prehistoric and Classical Antiquities, Theodora Karagiorga, complemented by a more systematic investigation conducted by the same person between 1989 and 1990. An additional excavation on top of the hill will add more light to the early history of Ptolis, which was founded by Mantineas, the mythical grandson of Pelasgos, the first parent of Arcadians.