Archaeologists excavating at Saint-Georges-de-Didonne in south-west France have uncovered substantial remains of a medieval seigniorial stronghold that once commanded a strategic position overlooking the Gironde estuary.Image Credit : Pierre Texier
The excavation, led by France's National Institute for Preventive Archaeological Research (Inrap), is taking place ahead of the construction of social housing. Across a 6,475-square-metre area, researchers are investigating the monumental defences of the former Château de Didonne as well as the medieval settlement that grew around the fortress.
Although the castle itself has disappeared, its enormous defensive ditches and traces of the surrounding community are revealing how the site developed from an earlier settlement into an important centre of local power.
The Discovery
The excavation has exposed evidence of two substantial concentric moats surrounding the former fortress.
The inner moat measures almost 15 metres across and reaches at least 6.5 metres in depth relative to the presumed base of the castle's curtain wall.
Along its inner edge, archaeologists have identified a massive reinforced rock embankment measuring at least 10 metres wide. Its complete extent remains unknown because part of the plateau lies beyond the excavation area.
The embankment was supported by stepped rockfill reaching at least five metres in height. Marl and a vegetated layer subsequently covered the structure, while its core consisted of organic or limestone deposits.
Researchers believe much of this material may have originated from the excavation of the moat itself.
The defensive structure dates to no later than the 12th century and demonstrates the substantial resources invested in protecting Didonne.
What Archaeologists Found
The outer defences provide further evidence of the fortress's scale.
A relatively empty strip of ground approximately 10 metres wide separates the inner ditch from a second moat. The outer moat is also around 15 metres wide, although it is shallower, reaching approximately 2.7 metres in depth.
Both ditches drain towards the damp Riveau valley.
One of the questions now facing archaeologists is whether the two moats were constructed as part of a single defensive scheme or whether the outer ditch was added later as the castle's fortifications were reinforced.
Beyond the monumental defences, researchers have also uncovered evidence of a medieval village associated with the stronghold.
Underground silos indicate the storage of harvested crops, while postholes reveal the presence of timber structures. Smaller ditches appear to have divided and organised parts of the settlement, and at least two wells have also been identified.
Historical Background
Historical records attest to the existence of Château de Didonne from at least the 11th century.
The stronghold occupied a strategically important position during the Hundred Years' War before eventually declining and disappearing from the landscape.
The castle stood on the slope of a limestone hill overlooking the marshy Riveau valley. Beyond the valley was a dune ridge bordering the Atlantic coast, close to the point where the Gironde estuary meets the ocean.
This location gave the medieval lords of Didonne an elevated position from which they could oversee access to the estuary and coast and monitor important maritime routes.
The site, however, was occupied before the castle reached its medieval prominence. Evidence indicates that sections of Didonne hill were already inhabited during the Carolingian period.
The excavation therefore provides an opportunity to examine a much longer history of settlement rather than simply the remains of a vanished fortress.
Scientific Analysis
The archaeological evidence is helping researchers reconstruct the sequence of development at the site.
The relationship between domestic remains and the monumental defences is particularly important. In some areas, the excavation of the inner moat and construction of its reinforced embankment cut through or covered earlier domestic features.
This indicates that people were already living in parts of the area before some of the major defensive works were constructed.
Researchers can therefore compare the settlement evidence with the development of the castle to establish how the growth of the fortified centre affected the surrounding community.
The two moats also present an important chronological question. Archaeologists must determine whether they formed a single defensive project or whether the outer moat represents a later strengthening of the castle.
Why This Discovery Matters
The excavation provides unusually detailed physical evidence for a stronghold that has largely disappeared above ground.
The monumental scale of the moats and reinforced embankment demonstrates the importance attached to defending Didonne. Its position beside the Gironde estuary further explains why control of the site could have carried strategic value.
At the same time, the discovery of the medieval village shifts attention beyond the castle's military role.
The silos, wells, timber structures and smaller ditches provide evidence of everyday life around the fortified centre. Together, these remains allow archaeologists to investigate the relationship between seigniorial power and the community that lived in its shadow.
The evidence for earlier Carolingian occupation adds another dimension, suggesting that the site's importance developed over a much longer period.
What's Next?
The excavation is continuing as researchers investigate the 6,475-square-metre site.
Further work may clarify the construction sequence of the two moats and establish whether the outer defence was added after the initial fortifications.
Archaeologists will also be able to examine the medieval settlement in greater detail, comparing domestic remains with the castle's defensive structures.
Understanding when the village developed, how it was organised and how its buildings were affected by later fortification work could provide a more complete picture of life at Didonne.
The research may ultimately reconstruct the transformation of the site from an earlier settlement into a fortified centre of seigniorial power overlooking one of the most strategically important waterways of south-western France.
Conclusion
The lost Château de Didonne has disappeared from the modern landscape, but its enormous defensive works have survived beneath the ground.
Archaeological excavations at Saint-Georges-de-Didonne have revealed two substantial moats, a reinforced rock embankment and the remains of a medieval village containing storage silos, timber structures, wells and smaller boundary ditches.
The discoveries show that Didonne was more than a military stronghold. It was a long-lived centre of habitation and local power whose development stretched back at least to the medieval period and possibly earlier.
As excavation continues, the site could reveal how a settlement overlooking the Gironde estuary evolved into a strategically important fortress — and how the community around it adapted to the rise of seigniorial power.
Sources : Inrap
FAQ
Where was the medieval stronghold discovered?
The remains were uncovered at Saint-Georges-de-Didonne in Charente-Maritime, south-west France, overlooking the Gironde estuary.
What was Château de Didonne?
Château de Didonne was a medieval seigniorial stronghold whose existence is documented from at least the 11th century. It later played a strategically important role during the Hundred Years' War.
How large were the castle's moats?
The inner moat was almost 15 metres wide and at least 6.5 metres deep relative to the presumed base of the curtain wall. The outer moat was also around 15 metres wide but approximately 2.7 metres deep.
Was a medieval village found?
Yes. Archaeologists uncovered underground storage silos, postholes from timber buildings, smaller ditches and at least two wells associated with a medieval settlement outside the castle.
Did people live at the site before the castle?
Evidence suggests that parts of Didonne hill were occupied as far back as the Carolingian period, several centuries before the castle reached its medieval prominence.
