The original castle in n a rocky spur was supposedly built in 413 by the Visigoths on the side of a mountain, defended by almost inaccessible cliffs. This fortress controlled the Arnette and the Thoré valleys, overlooking the plain where the town of Mazamet now stands.
Pierre-Raymond de Hautpoul is the first known lord of Hautpoul (mentioned in 1084). He rebuilt the castle, constructed the town walls and built the fortified church of Saint-Pierre d'Hautpoul. He accompanied his suzerain Raymond IV of Toulouse on the First Crude to the Holy Land in 1098.
In the 13th century, the lord of Hautpoul and Auxillan was Izarn d'Hautpoul. He reputedly adopted the Cathar faith. The castle and town was besieged by Simon de Montfort in 1212 during the Crusade against the Cathars of the Languedoc. The town was occupied and burned. Its fortifications were destroyed. However the survivors seem to have returned to Catharism as soon as the Crusaders left.
Around 1560, Huguenots (French Protestants) appeared in the region. The castle was besieged again during the wars of Religion between Catholics and Huguenots.
Today, you can still see the long village of Hautpoul winding down the hillside, along with the vestiges of upper and lower castles. At its foot, the river Arnette still winds, and its waters are still perfect for making wool. The old lower town gate has been restored, with its meurtrière. The village is being rejuvenated: picturesque old houses are occupied by craftsmen and their workshops.
References:The Château de Foix dominates the town of Foix. An important tourist site, it is known as a centre of the Cathars. Built on an older 7th-century fortification, the castle is known from 987. In 1002, it was mentioned in the will of Roger I, Count of Carcassonne, who bequeathed the fortress to his youngest child, Bernard. In effect, the family ruling over the region were installed here which allowed them to control access to the upper Ariège valley and to keep surveillance from this strategic point over the lower land, protected behind impregnable walls.
In 1034, the castle became capital of the County of Foix and played a decisive role in medieval military history. During the two following centuries, the castle was home to Counts with shining personalities who became the soul of the Occitan resistance during the crusade against the Albigensians.