It is a small (100 person) community famous for the (ruins of) its fortification, the Château de Montségur, that was built on the mountain on the ruins of one of the last strongholds of the Cathars.
In 1243–44, at the end of the Albigensian Crusade, the Cathari who had sought refuge at the Montségur fortress were besieged by 10,000 troops for nine months! In March 1244, the Cathari finally surrendered.
They had the choice to convert to traditional catholicism or to be killed. Approximately 220 refused to recant and were burned en masse in a bonfire at the foot of the mountain!
The current fortress (by now also in ruins) was built in the late 13th century by royal forces to guard the southern frontier.