2015-2016: restoration work at the Château de Clisson

Restoration work on the northern curtain wall of the Château de Clisson is currently being carried out by the Loire-Atlantique Department, due to the earth pressure of the north-east terrace of the Château de Clisson. The project is headed by the Chief Architect of Historic Monuments, Pascal Prunet.

The objective of the work is twofold:

• Significantly reduce the weight of the embankment by replacing some of the soil with a lighter material.
• Consolidate the vault of the underground gallery built into the base of the rampart, which is more than nine metres high outside the château.

Based on the 5-meter deep digging operation in an unexplored area of the château, the regional archaeology department of the Pays de la Loire Regional Directorate for Cultural Affairs ordered a preventive excavation operation on the project site. The Department contracted with INRAP to carry out the excavation operation from November 2015 to January 2016.

After the archaeological excavations, consolidation work on the curtain wall continued throughout 2016.

A primitive surrounding wall and a vaulted gallery are some of the medieval and modern vestiges unearthed by INRAP archaeologists on the north-east terrace of the château de Clisson, a historical monument at the confluence of the Sèvre and Moine rivers. These discoveries provide new knowledge about the history of the château and the evolution of its northern defensive front. The operation ordered by the regional archaeology agency is part of the restoration work carried out by the Loire-Atlantique Department. As the owner of the site, the Department pays particular attention to the archaeological study and restoration of the heritage for which it is responsible. These unprecedented discoveries are in line with the goals of conservation, restoration, scientific study and public dissemination of the results.

A primitive surrounding wall

Built on a rocky spur in the 11th century, the Château de Clisson became a strategic stronghold on the border of the Duchy of Brittany in the 15th century. In the 16th century, the defensive system was reinforced by the construction of a north-western bastion, a north-eastern terrace and a cavalier linking them.

During the excavation of the terrace, several built structures were discovered. Archaeologists uncovered a north-south wall in front of the main residential building. Probably defensive, this medieval wall is built of cut granite blocks joined with lime mortar. It is about 1.80 meters wide and 7 meters high. It is the oldest archaeological vestige unearthed at the Château de Clisson.

The evolution of the north face of the Château de Clisson

The archaeologists also found a gallery, built later, which delimits a space adjoining the northern side of the main residence. The gallery includes a corridor and a door at the western end opening onto the interior of the château. The corridor, which is 30 metres long and about one metre wide, forms a bend before leading to a postern (outer door) to the east. The ceiling is formed by a semi-circular vault that features seven vertical shafts, whose role is unknown: domestic or defensive? The external facing of the gallery, visible from the main residence, is quite exquisite.

In the 16th century, many improvements were made, leading to changes in traffic patterns. A curtain wall was built above the gallery, as well as a spiral staircase. The vertical shafts were blocked off and abandoned. The space between the residence and the gallery was filled in to create an exterior platform overlooking the town’s bridge. These improvements, carried out at the same time as the north-west bastion and the cavalier, considerably modified the appearance of the north side of the Château.

Daily life in an aristocratic residence

In the embankment of the north-east terrace, archaeologists unearthed objects that shed light on what life was like in an aristocratic residence of the modern period (16th-17th centuries). The items include numerous fragments of kitchen ceramics, such as drip pans, cooking pots, jugs, plates, etc. A small intact bottle could have been used to contain body oil, while a fragment of an albarella (small cylindrical vase) could have been used for medicine.

A few metal items were identified, including a key with a diamond-shaped head, pins, an item presumed to be a padlock and a Nuremberg token (accounting token) placed in circulation between 1490 and 1550.

Finally, a great many glazed or decorated terracotta tiles, shale slates and roof tiles were collected. All of these finds will provide valuable information about construction techniques, the use of materials through the ages and the decorative styles in aristocratic homes.