From Roman legionnaires to cathedral builders: the excavation of the Place du Château in Strasbourg

The origins de Strasbourg coincide with the installations of the Roman army. The Legio VIII Augusta was established in the Antique city of Argentorate in the 90’s AD. Its 6000 men built a permanent camp covering nearly 20 hectares, which would later become the core of the Episcopal city during the Middle Ages, now the current center of the city. In the context of several previous operations, Inrap archaeologists have already explored this camp, including the rue Brûlée in 2008 where part of the barracks of the legionnaires was uncovered. Today, the excavation of the Place du Château concerns another part of the camp, the praetentura, which contains, among other things, the houses of six tribunes and other barracks of the legionnaires and their centurions. 

Despite the small area excavated, the exploration of a single trench, 1.10 m wide and 3 m deep, has yielded several walls. One of the partition walls, which collapsed all at once, has a high quality mural painting on both of its sides. One painting represents columns and a panel framing a standing woman. The other consists of a beautiful red garland with a green knot. This painted plaster illustrates the status of the occupant of this building, who must have been a tribune, or at least a centurion. The two paintings were carefully removed and are currently being cleaned and restored. 

The earliest cathedral, whose location is unknown, appears in texts dated to 728. In 982, Strasbourg became an urban Episcopal Seigneury whose administration was tied only to the Diocese. In 1015, the Bishop Werner de Habsbourg undertook the construction of a new Ottonian style cathedral, which burned down in 1176. From 1180 to 1439, the current cathedral was built, first in a Roman style, and then in a Gothic style starting in 1255. 
With its 3 meters of stratigraphy, the excavation of the place du Château reveals the history of the constructors of the cathedral. 

Just to the south of the cathedral, the archaeologists have uncovered the levels on which the builders circulated. These levels are composed of flakes of sandstone spread out the stone cutters in front of their workshops (the loggias). Packed down by continual trampling, these stone fragments were accumulated from the 7^th to the 15^th centuries to a thickness of 1 to 1.5 meters. These stone fragments provide information on the stone cutting techniques used as they still display the traces of the tools employed, including picks, kevels and polkas. Other trades are also represented: the presence of slag indicates smithing activities, layers of mortar the work of mixers, and lead and glass fragments the work of master stained glass makers. The function of an oven with a single heating chamber, dated to the 12^th century, remains to be determined. 

A building from the 18^th century was partially uncovered in front of the Œuvre Notre-Dame. It was constructed on medieval foundations. According to the archives, it was built in 1724 in the location of a group of houses that included the stables of the Œuvre. The paving that is now visible, along with the study of the plan-relief of 1727, a watercolor and a map from 1854, reveal that some of these stables continued to function while the floors above were rented to individuals. This building was named after one of its renters "Maison Schoettel” in the 19^th century, before it was demolished in 1855 to enlarge the "Place du Palais” 

The opening of the last excavation sector, in front of the Fustel de Coulanges high school, and continuing research, have both provided additional information on the two millennia buried under the current Place du Château at the foot of the Strasbourg cathedral. 

The Place du Château is an emblematic site in Strasbourg and its history. Located against the southern side of the cathedral, it is surrounded by fine buildings constructed over several centuries. In our current car-dependent, it was transformed into a parking lot. In 2010, the Place was returned to pedestrians and a first project was developed. Its objective is to create a pleasurable space, to reveal the monuments surrounding the Place – with the first priority being the cathedral – to create views of the ensemble, and to draw visitors to the five museums on the Place.