The Tours amphitheatre (also known as the Caesarodunum amphitheatre) is a Roman amphitheatre located in the historic city centre of Tours, France, immediately behind the well known Tours cathedral. It was built in the 1st century when the city was called Caesarodunum. It was built atop a small hill on the outskirts of the ancient urban area, making it safe from floods, convenient for crowds and visitors, and demonstrating the power of the city from a distance. The structure was an enormous, elliptical structure approximately 122 metres by 94 metres. According to its design it is classified as a "primitive" amphitheatre. Unlike the famous Colosseum that was made mostly of masonry and built above-ground, the Tours amphitheatre was made mostly of earth and created by moving soil and rock into a bowl shape. Spectators likely sat directly on the grassy slopes, while the masonry was primarily used for the vomitoria and retaining walls.
When it was expanded in the 2nd century (to 156 m X 134 m), it became one of the largest structures (among the top ten) in the Roman Empire. It is not clear why the amphitheatre was expanded given the population and slow growth of the city at the time. About a century later, this expanded amphitheatre was transformed into a fortress, with an addition of a rampart-style wall, typical during the decline of Roman Empire. It gradually fell into ruin during the Middle Ages and canonical houses were built upon it and gradually concealed it. The vomitoria were at some point transformed into cellars.
The amphitheatre was then completely forgotten until the 19th century, when it was rediscovered (1855). Evidence such as the layout of the streets and radiating lots of the district drew attention to its existence. Surveys and terrain analyses in the 1960s gathered further data on the cellars of the houses which were previously built on the amphitheatre walls. Over the past decade, more in-depth studies of the topography and architecture have taken place and are changing the theories and opinions surrounding this monument.
The remains of the amphitheatre are not protected as historic sites directly; however, some of the houses built upon it are registered as historical monuments. The ruins of the amphitheatre are significant as they are among the oldest known ruins in the city, and offer clues about the early history and development of the area.
In the ancient city
Tours at the height of the Roman Empire
The city of Tours (known as Caesarodunum in Roman times) was established in the valley between the Loire and Cher rivers, probably during the reign of Augustus or Tiberius (between 10 BC and 30 AD). The ancient city was at least 80 hectares in size and heavily populated along the Loire River. Discoveries thus far indicate that it had at least one temple, two spas, two aqueducts, bridges and an amphitheatre. The city reached its peak at the height of the Roman Empire in the second century before shrinking, during the decline of the Western Roman Empire to the area in and around a Roman castrum whose amphitheatre is one of the structural parts.
Site The amphitheater was built in the suburbs at the northeast part of the ancient city, immediately southeast of the existing cathedral. The choice of this site corresponds to both the urban planning of the time and the layout of the land. Archaeologists believe the amphitheater was built on a natural sedimentary rock hill, which minimized masonry work by having it partially built into the rock. Being the middle of a low-lying flood plain, this also provided flood protection. The urban planning was such that the amphitheater had to accommodate large numbers of spectators, from within and outside the city and had to allow space for crowds around the monument. Given the size of this initial urban footprint, it is estimated that the population of the city was about 6000 people when the amphitheatre was constructed. The high ground upon which the amphitheater was built also allowed for the demonstration of wealth and power from a distance, a characteristic that was considered very important in the urban planning decisions of the Roman Empire.
History Studies conducted up to the late 1970s presented an image of a monument that was relatively homogeneous in its construction, built in a single period (early second century). Research in the twenty-first century, however has presented a different picture. The current theory is that the amphitheater was originally built in the first century and then altered at two separate times; first it was altered by expansion in the second century creating an amphitheatre almost twice the size. It was again altered in the third century, permanently transforming it into a fortification. This fortification would then serve as a starting point for an even larger enclosed area, known as a castrum, that would be built around 350 A.D.
Original structure
The Tours amphitheater is classified as a "primitive" amphitheatre, based on its design, not necessarily its age. It is as large as the amphitheatres in Samarobriva (Amiens), Octodurus (Martigny, Switzerland) or Emerita Augusta (Mérida, Spain). Another characteristic these amphitheatres share is that the cavea is not contained in the radiating walls and arches, as is seen in the Nîmes Arena, but rather within an outside embankment that slopes towards the arena. In Tours, the excavation of land in the arena during the original construction helped form this embankment. Spectators likely sat directly on the grassy slope of the embankment, but it is possible wooden bleachers (yet to be discovered) may have been used. Another primitive feature is the lack of stone steps and minimal masonry employed. For example, masonry was primarily used for the outer wall, the arena wall, galleries or vomitoria, and some radiating retaining walls.
The dimensions of this pseudo-elliptical amphitheater in the first phase of its existence, are estimated at 112 metres for the major axis and 94 metres for the minor axis. Its estimated area is 8,270 metres2. This is based on research as of 2017. The dimensions of the arena were approximately 68 metres by 50 metres with an area of 2670 m2. The 5600 m2 of the cavea could accommodate at least 14,000 spectators. The structure had eight vomitoria, four of which were the primary entrances and allowed access at the arena level as well as a higher level of the cavea. The other four were secondary, leading to the middle part of the cavea via stairs. The north and south vomitoria had a vault height of about 7.5 metres and a width of 4.9 metres; vomitoria on the west were smaller, measuring only 6.8 metres high and 2.5 metres wide. There were likely eight additional entrances, as it likely had a double exterior staircase at the front of the amphitheater similar to the amphitheatre of Pompeii. The orientation of the amphitheater was deliberately aligned with the city's street plan: its minor axis continues towards the west, along the Decumanus Maximus of the city, while its long axis is parallel to Cardo.
The entrances were paired vomitoria assembled into large blocks with sharp joints, the piers were topped with molded capitals that support a semicircular arch. The ramparts of Tours, made later during the falling Roman Empire, has many blocks that were likely reused from the amphitheater facade. The rest of the masonry of the walls and vaults of the amphitheater, was likely built from small rubble limestone cement (opus vittatum) without inclusion of terracotta, enclosing the stone blocks in concrete.
The construction dates back to the second half of the first century, or at least fifty years after the founding of Caesarodunum (Tours). It was at this time that most ancient monuments of Tours were likely built. This is based on the comparison of the architectural elements of the amphitheater of Tours and those of Amiens, Autun or Saintes, three monuments which have been precisely dated.
Expansion
The characteristics of the masonry (e.g. wall thickness was only 1.4 metres) indicate that the amphitheatre was expanded in the second half of the second century. While the overall dimensions of the amphitheater exceeded 156 × 134 metres, the size of the arena itself did not change. The capacity, however, more than doubled, having increased to allow for about 34,000 spectators. In this configuration, the amphitheater was extended in its southwestern part, beyond the existing retaining wall of the Général-Meusnier Street, thought to be the outer wall of the structure. The height of the amphitheater was estimated to be about 25 to 28 metres in the 1970s. More recent discoveries, however suggest this values is closer to between 15 and 18 metres.
There are numerous hints that show that the expansion was a renovation project. For example, the width and height of the main vomitoria vary significantly at the junction of two phases of work; two half-diameter reinforcements were built on either side of the entrances to increase the load bearing capacity (see Fig. 1), given the increased height (and weight) along the edge where the mass backfill rose sharply.
These construction features have been identified, in several points of the amphitheater and it is not yet possible to say if this same pattern occurred to the entire monument.
During the expansion, the external staircases of the original amphitheater were found embedded in the new embankment. Without being abandoned, they may have been vaulted and connected to the main vomitoria, becoming intermediate steps. Secondary vomitoria do not appear to have been extended to the new facade by corridors, but they may have been connected to a circular gallery on the ground floor. There is no direct evidence that new outside stairs were placed against the front wall, however there is indirect evidence to suggest that there were once stairs. For example, the cutaway front is attributed to towers made at the time of construction of the castrum. Also, the front wall seems devoid of any decorative element, based on the few remains available for observation.
Fortification added
In the second half or towards the end of the third century, the upper part of the cavea was 8 metres above the level of the arena. An annular wall was constructed without the use of quoin tiling and without large recycled stone blocks (from other dismantled buildings) included in its foundations. It was therefore constructed prior to the castrum, who saw these techniques implemented. The stone mixture of the wall was comparable to the enlarged amphitheater, however the wall obliterated some of its structures, indicating it was made after those structures. With a thickness of 3.5 metres and a height probably above the level of the cavea, the defensive wall was placed continuous along the entire on the embankment. This hypothesis is supported by the fact that the side vomitoria and indoor stairs were completely blocked, leaving the main vomitoria as the only access to the arena (facilitating defence). Moreover, there was a defensive moat preceded by a counterscarp, dated from the second half of the third century and dug at the foot of the amphitheater. While the remains were discovered in the southeast part of the structure, it was probably completely encircled the amphitheatre. Its maintenance ceased with the building of the castrum.
Comparable stone masonry, dating from the same period, exist in Avenches (Switzerland), Lillebonne and the arenas of Senlis. In each case the massive character of a monument, theater or amphitheater, was converted into a fort and offered temporarily shelter to nearby residents in case of attack. This would have been far less labour-intensive than building a fort from scratch.