Château de Bassoues, Square keep in Bassoues, Gers, France

Château de Bassoues consists of a square keep built in 1368 by Archbishop Arnaud Aubert and a residential building rebuilt in the 17th century. The keep rises 43 metres, measures 8 metres on each side, and has walls over 2 metres thick. Its top carries a walkway on machicolations, and a stair turret stands on the north side.

Arnaud Aubert, Archbishop of Auch, began the keep in 1368 to protect the bastide of Bassoues during the Hundred Years' War; accounts show it nearly finished at his death in 1371, and his successor Jean Roger de Beaufort continued the work. The castle was remodelled in the 15th and 16th centuries, then fell into ruins in the 17th century, when Archbishop Henri de La Mothe-Houdancourt rebuilt it with a wing flanked by two corbelled towers. The keep was classified as a monument historique in 1840, the first in the Gers; the castle was inscribed on 14 March 1944.

The keep was built from 1368 for Arnaud Aubert, archbishop of Auch, to protect the bastide of Bassoues. His arms are carved on the fireplace of the second vaulted floor, and the south wall holds the shared flue of the fireplaces. The castle later passed to Henri de La Mothe-Houdancourt, who rebuilt the logis in the 17th century.

The keep stands within the castle courtyard, reached on foot from the village of Bassoues; the first vaulted level on ogives was the entrance to the living quarters. The square tower measures 8 metres on each side, with walls over 2 metres thick, and is flanked by buttresses at every corner and a stair turret on the north side.

The keep's south wall holds a single flue serving fireplaces on all four floors, and the second-floor fireplace carries the coat of arms of Arnaud Aubert, who began the tower in 1368. Latrines sit inside the buttresses at each corner, and a carved niche holds a washbasin.