The Gallo-Roman baths of Tours were public bathhouses that, during the and for some until the end of the Roman Empire—none of them "survived" beyond that—were in operation in the ancient city of Caesarodunum, which would later become Tours. While these baths had long been widely accepted, their exact location began to be more clearly established in the 1980s.
Two monumental complexes were partially uncovered during excavations conducted between 1974 and 1979 for one, located in the northeast of the open city of the High Empire, which archaeologists refer to as the "Eastern Baths," and between 1999 and 2002 for the other, located in the south and called the "Southern Baths." Although excavations have not determined their exact extent, they seem to be located on the periphery of the ancient city or, at the very least, away from the most densely built-up areas. The Southern Baths were probably situated along one of the main roads of Caesarodunum, while the Eastern Baths were built along the Loire River. One or even two other public baths, of smaller size, may have existed—one to the west of the city and another to the south—but the evidence for their existence is very weak. The architecture of all these bath complexes is poorly understood, as excavations have only revealed a very small portion of their structures. Likewise, the details of how they were connected to water supply and drainage networks remain highly uncertain.
The remains of the Eastern Baths, which have been preserved, were reburied (it is possible to uncover them again in the future), whereas those of the Southern Baths were sealed under modern constructions after archaeological study. The rare masonry structures attributed to the baths located in the west are visible in an archaeological garden that traces the history of the site, which has been occupied almost continuously since Antiquity. The very tenuous evidence of a fourth thermal establishment disappeared after being studied.
Baths in the ancient city
General topography of Caesarodunum
The ancient city of Caesarodunum, likely a foundation ex nihilo from the beginning of our era, covered approximately 80 hectares on the left bank of the Loire, in the alluvial plain separating this river from its tributary, the Cher, near their confluence.
Although the topography of the city remains somewhat unclear, an embryonic street grid has been reconstructed and continues to be refined as new archaeological discoveries are made. The cardo maximus, which has completely disappeared from the modern cityscape, was probably located along the eastern edge of the Rue de Lucé, extending from a wooden bridge built over the Loire in the early 1st century. The decumanus maximus, running parallel to the river, is thought to be covered by the alignment of Rue de la Scellerie and Rue des Halles; it provided access to the amphitheater east of the city.
Near the intersection of these major axes stood the grand Gallo-Roman temple of Tours, as well as, most likely, the forum, although its exact location remains unknown.
Within this perimeter, urbanization appears to have been uneven, probably denser along the Loire. However, excavations conducted in 2006 and 2007, which were still being analyzed as of 2015, suggest the presence of a southern district in the ancient city with several contiguous domus accompanied by gardens, arranged in a well-defined parcel layout.
The presence of one or more public bath complexes in Caesarodunum has been hypothesized since the 19th century, by analogy with most other ancient cities. However, their location remained unknown for a long time. Until around 1850, historians believed they were located behind the cathedral, but the remains in that area were later identified as belonging to the amphitheater.
Water supply and drainage systems The water supply systems of Caesarodunum, particularly those intended for public use, have only recently begun to be understood, and likely in an incomplete manner. The most significant feature appears to be the Fontenay aqueduct, known since the 19th century, which transported water from multiple springs located 25 km east of Tours and probably entered the city from the south.
In 2003, an excavation site identified the position of the left bank of the Loire during the High Empire. At this site, an aqueduct perpendicular to the Loire, heading south toward the city center, was discovered. This aqueduct was fed by a noria that drew water from the river. However, this system appears to have had a relatively short lifespan, lasting only a few decades in the 1st century; it may have been a source of non-potable water intended for the city's artisanal activities. Nothing is known about the water distribution networks within the city that might have extended from the aqueducts.
As for drainage systems, gutters or sewers that could have evacuated wastewater from the baths have only been identified, as of the 21st century, at the Eastern Baths, and even then, only in their immediate vicinity. In the broader city, only two sections of a possible cloaca (large sewer), oriented north-south and possibly emptying into the Loire, were uncovered in the first half of the 20th century, but no link between this structure and the bathhouses has been established.
Southern baths
Between 1999 and 2002, reconstruction work within the grounds of the led the (INRAP) to conduct a preventive excavation operation. This consisted of six separate digs across the 1,000 m² affected by the reconstruction project.The Descartes High School in Tours occupies the entire western portion of the block bordered by Rue de la Préfecture and Rue des Minimes on one side and Rue Nationale and Rue de Buffon on the other, covering approximately 13,000 m².The coordinates were obtained from Google Maps archive.
It was already known that this area contained a fossil channel of the Loire, which had been largely filled in during Antiquity. This north-east to south-west oriented channel appeared to mark the southern limit of the urbanized area. Therefore, the discovery of ancient buildings constructed within this paleo-channel was a surprise for archaeologists. The site underwent multiple restructuring phases during the , with each new phase erasing previous structures. Furthermore, it was heavily disturbed in 1939 when air raid shelters were built as part of France’s passive defense efforts. These factors made it difficult to analyze the site. Additionally, the limited excavation area did not allow for a complete reconstruction of the uncovered baths.
A chosen location The Southern Baths were located in the southern part of the ancient city, in an area that, while built up, was probably not densely urbanized. During the High Empire, a major north-south road, identified as the cardo maximus, ran along the eastern side of the baths. Another parallel road, discovered beneath Rue Nationale during tramway construction in 2011, likely bounded the baths to the west. Perpendicularly, a decumanus likely ran along the northern edge of the baths, while another to the south, covered by Rue des Minimes, further defined the area.
The chosen location, within the bed of the paleo-channel, while imposing architectural constraints on the foundations of the buildings, may have been advantageous for facilitating the drainage of wastewater from the baths.
The installation of thermal establishments in the peripheral districts of cities seems to have been a fairly common practice in Roman Antiquity. In a city where wood still played an important role in building architecture, the outlying position of the baths limited the risk of fire spreading; smoke pollution was also reduced; finally, a large area was necessary to accommodate all the buildings of the thermal complex.
From restructuring to reconstruction
Before the baths The Southern Baths were not built in an area free of prior human occupation. Final Bronze Age ceramics (900-600 BCE), sealed between two layers of alluvium, were discovered; however, they may have been transported by floodwaters carrying the alluvial deposits. The beginning of the Gallo-Roman period (20-60 CE), which coincided with the founding of the city, has yielded remains of habitations (postholes) and craft activities (bronze-smelting furnaces). As early as 1977, a Gallo-Roman archaeological layer had already been identified on the site of the Lycée Descartes.
Initial phase During the last third of the 1st century CE, a period that saw the establishment of most known public monuments in Caesarodunum, new constructions appeared on the site. However, they were severely damaged by later modifications, leaving few usable remains. The ground level was raised, partially using charcoal, likely for drainage and sanitation purposes. Deep foundations over one meter in depth, set on alder piles, and a wall measuring at least 30 meters long, suggest a public building or complex, oriented precisely in line with earlier constructions. These features, along with the presence of a fragment of suspensura reused in later construction and the attribution of subsequent remains to a bath complex, support the hypothesis that these ruins belonged to an earlier version of the Southern Baths. The operational period of these structures was surprisingly brief and precise—approximately 10 to 15 years, between 60 and 70-75 CE.Ceramics found in the backfill date to the year 60 (terminus post quem), while wooden piles used for later building foundations come from trees felled between 71 and 75 (terminus ante quem).
Monumental baths The following period (second phase of the baths) was characterized by monumental constructions, which were preceded by the systematic dismantling of earlier buildings, the leveling of unused sections, and a new ground fill. Additionally, the orientation of the buildings was slightly altered, possibly to mark a clear break from the previous phase. The foundations of the main load-bearing walls were set on oak piles, which were not force-driven into the ground but rather placed in trenches or individually dug holes. A similar method was observed in the foundations of the nearby grand temple. For the Southern Baths, the construction of the walls' foundations took place after 71 or 75 CE, as these dates correspond to the probable felling period of the trees used for the piles, determined through dendrochronological analysis.
The southern part of the excavated area is occupied by a basin, whose floor is covered with several successive layers of masonry. This basin, identified as a cold-water pool, is surrounded by stylobate walls (supporting colonnades), which seem to define a room or area in which the pool forms the central element. Another wall, apparently enclosing the complex—at least to the north—has been identified. This wall features a series of apses, which may have been used to house statues. Further north, another wall appears to form the outer enclosure of the baths. The complex is believed to extend eastward beyond the excavated area, where it may have included a palaestra. To the south, also outside the excavation zone, lies a vast masonry complex of undetermined function, which could be the section dedicated to the actual bathing facilities. This suggests that the Southern Baths covered several thousand square meters; excavations have revealed only a fraction of the remains, most of which remain buried beneath the Lycée Descartes. Further restructuring work, initially planned for 2004–2005, might have provided an opportunity to learn more about these baths. However, ten years later, these projects had not been undertaken.
A section of the apse wall, one of the rare remains preserved in elevation, extends for 1.50 meters and includes several layers of masonry. This section confirms that the wall facing was built using small limestone rubble with iron-marked joints between the stones.