The greatest part of Vienne’s archaeological heritage has still to be discovered. A few edifices are still emerging from the ground and we can consider that, today, about 2% of the archaeological heritage, including the archaeological site at Saint-Romain–en-Gal, have been studied effectively. Today, it is only through numerous hypotheses and reconstructions that archaeologists can offer a picture of the city, certain districts and a few buildings.
Knowledge of our urban heritage first comes from the most notable monuments or the most significant developments, from a restoration in situ of the site, which allows an understanding of them in their topographical setting. This dimension is particularly necessary for the Vienne urban area where there is a varied and complex topography. In the urban area composed of Vienne, Saint-Romain–en-Gal and Sainte-Colombe, there are numerous monuments or sites that should be visited, even if they have not yet been restored in the best of conditions, or if they are difficult to get to.
We see that, because they were carried out in a variety of ways, the restorations bear the mark of time. However, even today, the artefacts always undergo a certain amount of reconstruction which stops the erosion of masonry exposed to the weather, and makes it easier to interpret them.
Nevertheless, present-day restorations differ from those carried out up to the middle of the century: they try to respect what remains of the original vestiges as much as possible. The restorations are preceded by a study or a very precise archaeological excavation which helps put together very complete documentation on the original state of the buildings or their remains. In fact, it is important that we know, a posteriori, what comes from the original construction and what is the result of restoration, and even reconstruction. Ancient buildings (elevated or foundations) are rarely homogeneous. By revealing the changes buildings have undergone over time, archaeological studies allow us to make an informed choice about development of the site. Thus we can put more emphasis one period, or, if it isn’t detrimental to the final interpretation, show several stages of the history of the building.
It must be made clear that, paradoxically, if we want to preserve certain ruins or buildings in their original state and show them to the public, the archaeologists must refrain from taking archaeological finds apart, particularly stonework (almost exclusively what is open to the public). This is at the risk of not recording all the data that can help us learn about the edifices.