A collapse of the natural dam on the lake at the foot of the site caused the destruction of part of the town of Mirepoix, 30 km to the north, in Ariège in 1279.
She asked that the water level be lowered and work undertaken to accomplish this goal led to the collapse.
The coat-of-arms of Isabelle de Melun, who was the daughter of a Grand Chamberlain of France, still exists in the 'new' castle.
The instruments seen in the room are the bagpipes, flute, tambourin, rebec, lute, gittern, portable organ, psaltery and the bowed hurdy-gurdy.
The castle's functions were military: lookout and defence, unlike many buildings of the era which had religious goals.
The best preserved part of the castle, the square keep measures 15 m by 15 m with a height of 35 m. Originally, it adjoined the manor house.