Castelnaud or rather the "new château" was founded in the XII century. In 1214 it was taken and demolished by Simon de Montfort, the leader of the crusade against the
Albigeois.
For a brief period after the Treaty of Paris in 1259, Castelnaud recognised the sovereignty of the Duke of Aquitaine, Henry III of England. The dungeons and the façade
(the wall around the courtyard) were constructed at that time. The facade forms a buttress on the side exposed to attack.
In 1368 Magne de Castelnaud, the sole heir, married Seigneur Nompar de Caumont. The Caumonts became the Seigneurs of Castelnaud. In 1405 they sided with the
English. The châteaux was then attacked by the French who drew on the support of Beynac up to their definitive victory in 1442, following a siege ordered by Charles
VII.