Château de Billy

Château de Billy occupies a limestone promontory rising about 50 meters above the surrounding landscape, providing commanding views over the Allier River valley and the village below. The surrounding village is arranged in an almost circular pattern around this elevated position, highlighting the castle’s central role.

The upper courtyard, or “haute cour,” is enclosed by a polygonal defensive wall roughly 50 meters wide east to west and 40 meters from north to south. This wall is reinforced by six semi-circular towers positioned along the north, south, and west faces. A prominent châtelet — a fortified gatehouse featuring twin towers — guards the entrance on the western side. The châtelet’s pointed arch dates to the 14th century and includes a groove designed for a portcullis, a heavy sliding wooden gate used to secure entrances.

Dominating the eastern side of the enclosure stands a tall cylindrical donjon, or keep, constructed primarily in the 14th century and possibly heightened at that time. Attached to the donjon is a polygonal stair turret. Also notable is an octagonal watchtower known as “La Guette,” added under the rule of Duke Louis II of Bourbon. This tower would have served as an observation post overseeing the surrounding countryside.

Below the upper courtyard lies the outer bailey, or “basse-cour,” an oval-shaped enclosure extending over 120 meters in length and nearly 100 meters across. The curtain walls here adapt to the uneven terrain with a combination of straight, curved, and irregular sections. Arrow slits, specifically narrow vertical openings called “archères en rame,” characteristic of 13th-century royal fortifications, are distributed along these walls, providing defensive firing positions.

In the outer bailey, a captain’s residence and guardhouse were constructed during the 15th century. Prior to this addition, the captain responsible for the castle’s defense would have been housed within the donjon, particularly in a chamber named after Louis II of Bourbon. Archaeological surveys have uncovered foundations and remnants of various domestic buildings within both courtyards, including stables abutting the southern curtain wall and other service structures along the northern wall.

A chapel once stood adjoining the southern tower of the châtelet. Although it has since fallen into ruin, traces of painted vaults remain visible, indicating its previous decorative treatment. At the end of the 16th century, one of the northern semi-circular towers was converted into a prison cell, a function it maintained until the time of the French Revolution.

The castle’s walls and towers are primarily assembled from local limestone and sandstone, reflecting the region’s available materials. During the 20th century, partial restorations were undertaken to stabilize the fragile remains. The château’s ruins have been protected as a historic monument since 1921, with the outer enceinte recognized in 1929. Later, the entire village of Billy gained protection as a designated heritage site in 1975.

Today, visitors can observe the remains of this large medieval fortress, which clearly reveal the castle’s historical importance as both a defensive stronghold and a center of local power.