The sanctuary of Athena Pronaia is located to the southeast of the sanctuary of Apollo (Pedley 151). The sanctuary, or Marmaria, was visible to those arriving from the east, before arriving at the sanctuary of Apollo, hence the name Athena Pronaia, which means “Athena in front of the temple” (Pedley 152-153). The importance of the sanctuary was highlighted by a practice in which those who came to petition the oracle were first required to offer a sacrifice at the Athena Pronaia, who was the guardian of the Pythia (Luyster 148).
A terrace, measuring 150m x 40m, led to the several altars, temples, treasuries, and the tholos within the Sanctuary (Pedley 151). The largest building in the Sanctuary was the Archaic temple of Athena, containing several altars with the oldest dating to the 7th century B.C.E. (Pedley 151). There were two treasuries within the complex. While the origins of one is unknown, the other dates to the 6th century B.C.E. (Pedley 152). This treasury was dedicated by the inhabitants of Massilia in thanks for a victory over the Etruscans (Pedley 152). In front of the treasuries stood a trophy on a rectangular base to commemorate a Greek victory over the Persians (Pedley 152).
The tholos was constructed in the 4th century B.C.E. (Pedley 152). The architect, Theodorus from Phokaia in Asia Minor, built the circular structure which was 13.50m in diameter, encircled by twenty Doric columns on the outer circle and ten Corinthian columns on the inner circle (Valavanis 232). The outer structure was constructed of Pentelic marble and the walls were set on a layer of dark Eleusianian stone (Valavanis 232). The building was decorated with moldings and relief metopes in the diorama of the peristyle and wall (Valavanis 232).
While the function of the tholos is not completely clear, there are some theories about suggested usage (Valavanis 232). One possibility is that it was a chthonic cult dedicated to a god or local hero, similar to the tholos at Epidauros (Valavanis 232). Another suggestion is that the tholos was a circular treasury in which statues were kept, much like the Philippeion at Olympia (Valavanis 232).
In 373 BC a major earthquake caused stones from the Phaidriades rocks to fall, destroying the temples (Valavanis 232). Delphi was forced to seek contributions which were recorded on stone slabs erected in the sanctuary (Valavanis 234). Reconstruction began in 370 BC but ceased after a series of sacred wars (Valavanis 234). The Phokians, for political reasons, donated a huge sum of money, which was largely responsible for the continuation of construction (Valavanis 235).
The tholos at the sanctuary of Athena Pronaia at Delphi was built sometime between 400-375 BCE and was probably designed by Theodorus of Phocaea, who is said to have written a treatise devoted to the temple structure (Lawrence 1957, 184). The structure was constructed primarily of marble which was brought from Attica and is 13.5 meters in diameter. In recent years, the temple has been partially reconstructed; three columns have been restored along with partial cornices, pieces of the guttering, metopes, and triglyphs. Featured on the exterior friezes were images of the battle between the Amazons and the Centaurs. The gutter of the exterior Doric entablature was ornamented with lion head spouts. The blocks of the tholos are joined together carefully, and the joints coincide with the central points of the triglyphs and metopes. The blocks were stippled except for polished bands at the margins. Also done in the Athenian Propylaea, this method emphasizes the joints more than other smooth marble architecture of Athens.
The floor of the tholos is raised three feet above ground level and features a pteron of twenty Doric columns. The interior circular wall of the cella has a diameter of 8.41 meters and is lined with Corinthian columns which have alternating placement with the exterior Doric columns. The placing of the columns is considerably closer than in contemporary rectangular buildings. Arranging the pteron so closely was done specifically for aesthetic purposes in order to carry the viewer’s eye smoothly around the curve of the structure. The interior columns would have rested upon a bench of black or blue limestone rather than directly on the floor. Lifting these columns off the floor also aided the reduction of the cluttered appearance, which could have easily occurred because of the number and proximity of the columns. The cella floor was paved with the same black limestone, except for a circle of white marble in the center. Outside, the base of the wall was also black.
The doorway to the cella is a triple opening formed by two Ionic half columns which are engaged directly on top of piers and set between posts or pillars called antae. Inside the opening, the piers upon which the half columns rest have a line of diminution which coincides exactly with that of the half column, which makes the piers invisible from outside the opening. This opening would have been blocked with bronze or iron grilles in front of solid doors (presumably of wood).
Rising above the tholos were perhaps two distinct roofs (Lawrence 1957, 184), though recent publictions by the French School and the French National Power company suggest otherwise (Marmaria 1997). If there were indeed two roofs, from the cella rose a conical roof, while a separate roof sloped down from a lower level of the wall over the pteron. The form of the timbers which supported the cella’s roof is uncertain. J.P. Michaud suggests trusses, each of which has a horizontal element composed of two long, relatively thin beams which are placed side by side, but of which only a single beam would be inserted in the smaller sockets at either end of the cella (Michaud 1971). Smaller rafters at either end of the cella are explained by the fact that much of the weight of the actual roof would have been supported by the walls. Also possible is the existence of single large beams which would have been relatively load-bearing rafters. The rafters could have also been doubled, with single principle rafters coming underneath smaller rafters on top of which tiles could have placed. There are no records of roof tiles being found by excavators. This indicates the possibility that the roof collapsed in antiquity and the remains were removed. There is also discussion that the cella may have been lit by windows in the upper areas of the wall; however, no structural evidence of this has been found.
The circular shape of the tholos at Delphi is not unusual in Greek architecture, and in this case its shape, coupled with the leaf-adorned capitals of the Corinthian columns of the cella’s interior, are said to be representative of the sacred forests of the Earth Goddess Religion. Vincent Scully (1979) states, “The omphalos, or navel, which was supposed to mark the center of the world, was kept in the sanctuary of Apollo’s temple itself (in the center of nearby Delphi), but the tholos of Athena’s sanctuary more clearly seems to evoke the navel of the earth than does the other building there.”