The Gallo-Roman temple of Tours is an ancient religious building of the fanum type, dated to the late 1st century CE. It was located in the city center of the ancient settlement of Caesarodunum, which also corresponds to the heart of the contemporary city of Tours, in the Indre-et-Loire department.
It most likely succeeded an earlier sanctuary built in the first half of the 1st century at the same location. The temple belongs to the relatively small group of urban Celtic-inspired temples with a circular sanctuary, such as the Tower of Vesunna in Périgueux. Its cella probably measured over thirty meters in external diameter and stood at least twenty meters high. It was preceded to the east by a pronaos in classical Roman style, topped with a triangular pediment, and the entire structure was enclosed within a peribolus of about 0.7 hectares. The temple appears as the result of the merging of two religious and architectural cultures, although the reasons for choosing such a unique design remain unknown. Many elements of its architecture, decor, and surroundings remain undiscovered. Furthermore, historians and archaeologists know nothing about the dates of the temple’s abandonment and destruction, nor the identity of the deity or deities it was dedicated to. Nevertheless, from the Early Middle Ages onward, a necropolis occupied the site of this ancient monument, and a 15th-century urban wall reused some of its structures.
Its existence was revealed through medieval texts, but not its precise location. It was accidentally uncovered during the clearing of ruins in Tours after World War II and was quickly examined. The remains were destroyed in the urgent push for . The temple underwent two preventive or rescue excavation campaigns in the 1990s and around the turn of the third millennium; its immediate surroundings were partially studied in 2000 and 2011. Nowadays, only a few rare underground remains of this grand temple are known, all listed in the General Inventory of Cultural Heritage. However, other parts likely remain, sealed within the foundations of buildings reconstructed after the war.
Temple at the heart of the ancient city
Caesarodunum during the Early Empire
Probably founded during the reign of Augustus or Tiberius, between 10 BCE and 20 or 30 CE, Caesarodunum was established in the valley between the Loire and Cher rivers, at the site now occupied by Tours. The area of the ancient city is estimated to be at least 80 hectares, though urbanization was denser along the Loire. Caesarodunum had monuments and public facilities, including an amphitheater, two bathhouses, two aqueducts, a bridge, and the temple; other structures likely remain to be discovered. The city reached its peak during the in the 2nd century.
Location and orientation
The temple of Tours is located in the hypercenter of the 21st-century city, within the block bordered by Rue Nationale to the west, Rue de Lucé to the east, to the north, and Rue Émile-Zola to the south. It lies buried beneath the theater and the Regional Dramatic Arts Center.
According to prevailing hypotheses in 2014 regarding the road network of the city during the Early Empire, the decumanus maximus is identified with Rue de la Scellerie and Rue des Halles, while the cardo maximus roughly follows Rue de Lucé, extending from a wooden bridge over the Loire and leading south to public baths. These two main axes of the ancient city would have intersected northeast of the temple. The city’s heart, thus defined, would have centered around some of Caesarodunum’s public facilities, including the forum, an essential feature of Roman cities, even though exceptions to this rule exist. The forum has not been identified in Tours, but it could suggest its location within one of the three remaining quadrants of this strategic crossroads. Additionally, a source, possibly sacred, was discovered nearby and laboriously filled in 1952; this source could be linked to the forum, or even to the temple itself.
The temple faces almost precisely east and is aligned with other monuments of the ancient city. This orientation is a very typical arrangement for this type of monument, according to religious conventions. The pronaos facade forms a slight angle with the cardo maximus, slightly oriented southeast and northwest due to topographical constraints (to maintain orthogonality with the decumani and the ancient shoreline of the Loire).
Architecture and dating
A 3D animation available on the website of the (INRAP) offers a reconstruction of the temple, depicting a fanum-type structure that blends Celtic influences (circular cella) and classical Roman architecture (a pronaos with columns topped by a triangular pediment). This design represents a fusion of two religious cultures and architectural styles. Pierre Audin describes it as "a fortunate alliance between Romanization and loyalty to indigenous traditions." In this regard, the temple of Tours belongs to the group of large circular cella temples, including those of Barzan, Cahors, Périgueux, and Vendeuvre-du-Poitou.
The temple of Tours is large. The only confirmed dimension that allows for a comparison is the exterior diameter of the cella: 34.80 meters for the temple of Tours and 19.60 meters for the Tour de Vésone in Périgueux, a structure of comparable, if not similar, design.
Earlier structure preceding the temple Beneath the temple’s foundation level, predating it and directly dug into the natural alluvial soil,The natural ground level in this part of the city is at 47 m NGF, which is 4 m below the ground level in the 21st century () a trench from a previous wall was discovered. It was filled with debris, including fragments of red plaster that once covered this wall. The persistence of this plaster on the wall suggests it must have been protected from the elements, possibly by a roof. Marks from stakes and possibly a well, the coping of which had been dismantled, were also identified. The trench was dug into the natural soil, indicating that the wall was, chronologically, the first structure established in this area. A possible dating points to construction during Tiberius’s reign, with the site being occupied until the third quarter of the 1st century CE. The fragmentary nature of these remains makes interpretation difficult. However, a hypothesis suggests an initial Tiberian-Claudian cult complex (built between 14 and 54 CE) that directly preceded the large temple, reflecting continuity in the site's use. This early complex would have consisted, among other things, of a courtyard partially sheltered by a roof and possibly a cultic well.
Architectural components of the temple
Foundations
The foundations are established on a dense arrangement of oak piles,The use of wooden piles as a foundation base in wet areas was a widespread practice in antiquity. In Tours, where the water table was only a few meters below the surface, it is confirmed for the foundations of a public thermal establishment () and is presumed for other constructions, including the Late Empire fortifications (). with an average density of 15 piles per square meter, placed within a trench. The gaps between the piles are filled with liquid clay to hold them in place and prevent the formation of air pockets that would be detrimental to their preservation. These piles have a square cross-section of approximately 30 cm and measure between 1.50 and 2 meters in length. Their tips are carved into an elongated, four-sided pyramid shape. Some of the piles, taken from trunks of large diameters, were split with an axe and then smoothed with a saw before use. The preservation state is such that fragments of moss and lichen sometimes still adhere to the bark. Nine hundred of these piles were extracted during the 1994 excavations; the total number of piles supporting the temple’s foundations is estimated at 9,400. A waterproofing layer made of mortar containing tile fragments caps the ends of the piles. A 1.80-meter-thick masonry mass covers this entire arrangement. This mass is much wider than the walls’ elevation, as is generally the case. It serves as the base for the structure, but its layout seems irregular and does not strictly follow the assigned shape of the monument.In the captions of photographs taken in 1951 and presented in the Mérimée database of the Ministry of Culture, the foundation ring of the cella is mistakenly interpreted as a step structure providing access to the temple. The existence of the "monumental portico" mentioned in the notice is not referenced in any subsequent publication. Finally, the "room flanking the cella to the west" is likely, given the announced dimensions, the pronaos, which is not located to the west but to the east of the cella ().
The entire temple appears to rest on this type of foundation, designed to support heavy loads, except for the access staircase to the pronaos, whose foundation masonry mass rests directly on the ground.
Pronaos
The temple’s cella opens to the east onto a pronaos (also called a propylon), following a fairly classical layout for this type of grand monument. In his initial surveys, Raoul Lehoux referred to this part of the building as the "opisthodome," believing the temple opened to the west and that he had identified its rear section. The pronaos measures 27.50 meters in width, with a depth ranging from 7.50 meters at its center—aligned with the presumed entrance to the cella—to 10.40 meters at the side walls of the pronaos.This depth variation is due to the curvature of the cella wall. It forms a raised podium, 2.20 meters high, built on a masonry mass and accessible by a straight staircase of 11 steps, probably enclosed by side walls. The top of this podium marks the circulation level for the pronaos and the cella. Fragments of column drums and Corinthian-style capitals found nearby, as well as reused within the foundations of Tours’ Gallo-Roman enclosure, are attributed to this part of the temple. The pronaos was, in all likelihood, topped by a triangular pediment resting on a series of columns adorning its façade. However, the state of preservation of the column remains—around thirty in total—does not allow for precise measurements, making it impossible to determine their exact number (either six or eight). The total height of the pronaos, at the peak of the pediment, is estimated at 18.60 meters above ground level, or 16.40 meters above the podium, with its roof consisting of tiles covering a wooden framework and slats.
Cella