Queribus is one of the “Five Sons of Carcassonne”, along with Aguilar, Peyrepertuse, Termes and Puilaurens: five castles strategically placed to defend the French border against the Spanish, until the border was moved in 1659. It is sometimes regarded as the last Cathar stronghold. After the fall of Montségur in 1244 surviving Cathars gathered together in another mountain-top stronghold on the border of Aragon (the present border between the Aude and the Pyrénées-Orientales).
In 1255, a French army was dispatched to deal with these remaining Cathars, but they slipped away without a fight, probably to Aragon or Piedmont – both regions where Cathar beliefs were still common, and where the Occitan language was spoken. Quéribus is high and isolated. In 1951 restoration work on the turret began, and between 1998-2002 a complete restoration of the castle was undertaken: the castle is now accessible to visitors.