1If, from early on, historians and archaeologists have shown an interest in great feats of engineering such as Roman aqueducts, roads and fortified sites of all periods, or fields of megaliths and vast ritual or public buildings, from Roman amphitheatres to Christian cathedrals… we have had to wait a long time for an interest – beyond that dedicated to the monument and its academic study – in the site prior to its implantation or even how its building was organised to develop, apart from studying medieval iconography or archives relating to recent periods. Such preliminary works designed to make the ground ready to receive a building, e.g. drainage, soil stabilisation, retaining walls or excavation, or measures taken to make the building site efficient, such as the flow of materials, specialist workshops, shelters for people and materials … all these indicate how life was organised on site, how the work was conceived and demonstrate the know-how of the workers involved.

2Sporadic information has emerged in this field. At the Roman fortified complex of Jublains (Mayenne) painstaking work since the 1980s has shown how the teams engaged in the construction of the defensive wall were organised. Experimental work on the megaliths of Bougon (Deux Sèvres) has given us a clear idea of the procedures as well as the number of people needed for such operations. Analyses of the elevations or foundations of monuments sometimes reveal mistakes, corrections or modifications made by the architects or masons, such as, for example, the traces of a project by Claude-Nicolas Ledoux for the prison of Aix-en-Provence, abandoned shortly after construction began at the time of the Revolution and built later, but on modified plans.

3With the development of mitigation archaeology, which often means that large buildings and large public works are bypassed in favour of exploring their periphery or their subsoil, we have come to realise that we are discovering more frequently remains linked to the preparation and the unfolding of these major works… Even evaluation work on the “Seine-Nord-Europe” canal is revealing information on this subject. In the zone of Marquion (Pas-de-Calais) sandstone extraction pits backfilled with the offcuts from making paving stones have been found. These cobbles, made in the middle fields by the farmers during the winter season, were the consequence of the politic of road improvements on the damp plains and plateaus of the north. They remained famous in the history of sport as the “cobble stone inferno of the North” of the Paris-Roubaix race.

4Let us not boast too soon, as these remains are often slight, sometimes equivocal, and sometimes left unstudied for want of the ability to understand and interpret them. Let us not neglect them, they are just as precious testimonies to the ingenuity and know-how of our ancestors. They also often allow us to make the link between what doctrinal works, first amongst which ranks Vitruvius’ De Architectura or Alberti's De re aedificatoria, meant and the daily reality of the builders.

In Moulay (Mayenne), the capital of the Aulerques Diablintes territory in the 1^st century BC, the political authorities developed a vast fortified town.

Agrandir Original (jpeg, 2,5M)

This oppidum probably covered an area of 135 hectares. The town was laid out according to a planned urban development scheme, with a general orthogonal grid and organisation into specific neighbourhoods. Here, an aerial view of a residential area organised into housing estates (with standardised houses and their outbuildings) and grouped gardens: vegetable gardens, orchards?

Gilles Leroux, Inrap.