Château-Vieux, Medieval castle in Bayonne, France

Château-Vieux is a fortified structure at the northern corner of Bayonne's ancient walls that incorporates three Roman towers within its square layout. The complex functions as a cohesive defensive system where the ancient towers form the core of the entire construction.

The castle stands on the site of a Roman castrum that housed the garrison and administration of Lapurdum. From the end of the 11th century the Viscounts of Labourd built a fortress around three reinforced Roman towers as their residence. In 1295 the citizens of Bayonne drove the French garrison into the castle and opened the town gates to John St John; it surrendered after an eleven-day siege. In the 17th century Vauban made it the north-west strongpoint, destroying the keep and adding a fortified forecourt.

The fortress shows how residents of Bayonne defended their city across different eras and how living spaces connected to military needs. Walking around the exterior, you can still see the different building phases that reveal how the town's requirements changed over time.

The castle is an active military site, home to the 1st Marine Infantry Parachute Regiment, and its interior is not open to visitors. It can be viewed from the surrounding streets of Bayonne, where the pale facade, the darker projecting wall with its archway and the corner tower with its red-tiled conical roof are visible from outside.

In 1808 Napoleon Bonaparte signed a decree ordering the castle demolished; the order was never carried out, and the building still stands. Today it serves as the mess of the 1st Marine Infantry Parachute Regiment (1er RPIMa), continuing a military role that dates back to the Roman garrison of Lapurdum.