Archaeologists have uncovered substantial remains of a medieval seigniorial stronghold overlooking the Gironde estuary, shedding new light on a strategically important settlement that disappeared from the landscape centuries ago.
The excavation at Saint-Georges-de-Didonne, in Charente-Maritime, is being carried out by France’s National Institute for Preventive Archaeological Research (Inrap) ahead of the construction of social housing.
Across a 6,475-square-metre site, archaeologists are investigating the monumental moats of the former Château de Didonne, as well as evidence of the medieval village that developed around the fortress.
Although the castle itself has completely disappeared, historical records attest to its existence from at least the 11th century. It later occupied a strategically important position during the Hundred Years’ War before gradually falling into decline.
Today, the place name Le Châta and a network of imposing ditches are among the few visible reminders of what was once an important centre of local power.
Fortress guarded the entrance to the Gironde
The castle occupied the slope of a limestone hill overlooking the marshy Riveau valley, through which a now-channelled stream runs.
Beyond the valley lies the dune ridge bordering the Atlantic coast, close to the point where the Gironde estuary meets the ocean.
The position gave Didonne considerable strategic value. From the elevated site, its medieval lords could oversee access to the estuary and coast and monitor important shipping routes.
The latest excavation, building on an archaeological assessment conducted in 2012, has revealed that the fortress was protected by two substantial concentric moats.
The inner moat, immediately below the castle, measures almost 15 metres across and at least 6.5 metres deep in relation to the presumed base of the curtain wall.
Along its inner edge, archaeologists have uncovered an enormous reinforced rock embankment measuring at least 10 metres wide. Its full width remains unknown because the edge of the plateau extends beyond the excavation area.
The embankment was supported by stepped rockfill reaching at least five metres in height. This was subsequently covered with marl and a vegetated layer, while its core was formed from organic or limestone deposits.
Archaeologists believe much of this material may have come from the original excavation of the moat.
The structure dates to no later than the 12th century and points to the considerable resources invested in defending Didonne.
Second moat strengthened castle defences
Beyond the inner defences, a relatively empty strip of land about 10 metres wide separates the first ditch from a second moat.
The outer moat is also around 15 metres wide, although at approximately 2.7 metres deep it is considerably shallower than its inner counterpart.
Both ditches drain towards the damp Riveau valley.
One of the questions archaeologists hope to answer is whether the two defensive structures were part of a single construction project or whether the outer moat was added later as the castle’s fortifications were strengthened.
The scale of the defences provides some of the clearest physical evidence yet of the importance of the medieval stronghold.
Medieval village discovered outside castle
The excavation is also revealing how ordinary people lived alongside the fortified complex.
A medieval village developed outside the castrum, spreading across both the hillside and plateau surrounding the castle. Archaeologists have uncovered numerous features associated with this settlement.
Among the most common discoveries are underground silos that would have been used to store harvested crops. Postholes provide evidence for timber buildings, while a network of smaller ditches appears to have divided and organised the settlement. At least two wells have also been identified.
Some of the discoveries could help researchers establish the relationship between the development of the village and construction of the castle’s fortifications.
In places, the digging of the inner moat and construction of its reinforced embankment cut through or covered earlier domestic remains, indicating that people were already living on parts of the site before some of the monumental defences were created.
Evidence also suggests that sections of the Didonne hill were occupied as far back as the Carolingian period, several centuries before the castle reached its medieval prominence.
Together, the discoveries point to a long continuum of settlement at Didonne and provide archaeologists with an opportunity to reconstruct the development of an important centre of habitation, defence and seigniorial power at the entrance to the Gironde estuary.
While Château de Didonne itself has vanished, the enormous ditches and remains of the community that lived in its shadow are providing a new picture of the fortress and the role it played in medieval south-western France.
Sources : Inrap
