Excavation Uncovers Layers of Paris’s History Under Notre Dame

Tourists waiting under the summer sun to ascend the Notre Dame Cathedral are unaware of an archaeological excavation unfolding just four meters below. The team of archaeologists is delving into Paris’s Roman past, dating back 2,000 years.

In 2019, a fire caused the spire of Notre Dame to collapse, witnessed by the world. The cathedral has since been rebuilt and reopened at the end of 2024. Now, there is a desire to humanize the barren plaza with trees and shade. However, any construction in such an ancient city must begin with an excavation to prevent potential damage.

A section of the plaza has become an excavation site—a pit surrounded by barriers and accessed via a wooden walkway, close to the tourist queue. The French press has called it ‘the excavation of the century.’

“It’s a rare chance to work on something that will leave a tangible mark on Paris’s history,” said Lucie Altenburg, curator of Paris’s archaeology unit.

Among the artifacts found are a 4th-century coin with Emperor Constantine’s visage and medieval pottery with undeciphered marks akin to a modern Da Vinci Code.

Emily Carter, a tourist from Manchester, commented while waiting in line with her two children, “It makes Notre Dame feel alive again. You come to see the cathedral and realize there’s another city beneath your feet. It’s almost more moving.”

Layers of History Unearthed

The process revealed the first remnants at 50 centimeters deep. Four meters down, the team continues to unearth the past, often filling 15 boxes with untouched soil each day. This is the reality of ancient cities—history exists beneath the streets, not just in nearby museums.

Every era builds on the ruins of its predecessor, raising the ground level. Since the fall of the Roman Empire in the 5th century AD, Rome’s level has risen about 9 meters. Similarly, Athens’s metro construction for the 2004 Olympics led to Greece’s largest excavation, unveiling tens of thousands of objects now displayed in metro stations.

Paris’s history originates from the Seine island, Île de la Cité, the city’s founding site. Centuries later, Notre Dame rose on this land, where medieval homes once stood. Camille Colonna, leading the dig, notes that excavating to the basements touches upon the historical era they represent.

Beneath lie grain silos from the Merovingian and Carolingian periods, between the 6th and 10th centuries. Further down, a dense Roman neighborhood from the 4th and 5th centuries emerges. Twenty centuries of history stack within four meters, or roughly the height of two and a half Napoleons.

Mysterious Finds

The most intriguing discoveries come from deep waste pits under medieval homes, which doubled as garbage dumps. Excavators retrieved intact jars and cups amid broken plates and animal bones.

“It’s rare to find complete ceramics,” noted Valentine Breloux, an archaeologist from the unit. “Here, soft waste cushioned them, preserving them intact over the centuries.”

Moreover, conservators encountered interior reddish writing on seemingly medieval pottery—distinctive, mysterious marks yet to be deciphered. These are the most “astonishing” finds, remarked Breloux.

Coins Provide Historical Dating

The coins, appearing as corroded black discs, revealed under X-rays a Roman Emperor Constantine’s face from the early 4th century AD. Such items are invaluable for dating underground layers, explained Altenburg.

Roman artifacts, the deepest, oldest, and least understood, are highly prized by archaeologists. During the Roman Empire, Paris was called Lutetia, with its center across the river Seine’s left bank. As the empire fell, people retreated to the Île de la Cité, eventually home to Notre Dame. They fortified the island with stones from earlier structures.

The team found evidence: a Roman threshold turned into paving along a path during excavation.

Future Plans for Notre Dame’s Plaza

Every artifact extracted from the pit heads north to the city’s archaeology center—what Colonna describes as “a vast archaeological warehouse” and a Parisian treasure trove.

For archaeologists, the cathedral site is a unique venture. In France, digs occur only when construction is imminent, reminiscent of industrial quarry workers accidentally uncovering dinosaur remains.

“This is happening because Paris decided to enhance the area,” Altenburg explained. The revamped plaza should be largely complete by 2028, featuring 160 new trees and a thin water sheet cooling the stone surfaces, part of Paris’s plan to prepare for hotter summers due to global warming.

Tourists, currently in the relentless sun beneath the gargoyles, will soon queue in the shade. The former underground car park will reopen as a visitor center overlooking the Seine. Until then, the Notre Dame team aims to dig deeper, beyond the Romans, to the Gauls, who gave the city its first name.

“The hope is to delve deeper into time than ever before,” Altenburg added.

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Nicolas Garriga in Paris contributed to this report.

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This story was translated from English by an AP editor with assistance from a generative AI tool.