Scaffolding that had been erected for a restoration project at Notre Dame melted into the building during the April 2019 fire. Before workers removed this scaffolding, archaeologists had a unique opportunity to dig at the site. During this project, archaeologists from the French National Institute of Preventive Archaeological Research, overseen by Xavier Peixoto, dug three test pits. Two revealed little of interest, but the third brought to light a 10-foot-high medieval limestone quay wall that predates the Gothic church begun in 1163 and provides new evidence of the earlier history of the site.

The wall had first been discovered in 1918, at which time the lower part was dated to the pre-Roman Gallic period and the upper part to the Roman era. But according to Peixoto, the entire wall is medieval and dates to the end of the eleventh or first half of the twelfth century. “It’s an important find because it’s earlier than the cathedral and the episcopal palace of its builder, Maurice de Sully,” Peixoto says. “Its position seems to indicate that the location of the episcopal palace of the 1160s was further north than previously thought, and not under the new episcopal house built by de Sully.”

On top of the wall the team found a layer of fill corresponding to the period of the Gothic cathedral’s construction that Peixoto interprets as landfill needed to build up the ground to construct the new episcopal palace. Atop the fill layer, the team uncovered construction debris relating to work to extend the palace in the sixteenth century and a buttress dating to the 1300s that was found in a layer corresponding to eighteenth-century renovations of the cathedral. These discoveries provide evidence of the long and complicated history of Notre Dame that has until now rarely been seen.