How Carcassonne originally got its name is lost in antiquity.
However, there is a favorite local folk tale about how le Cité de Carcassonne got its name in the legend of Madam Carcas.
According to one version of the legend, in the 800’s Emperor Charlemagne’s troops surrounded le Cité in an attempt for the Frankish king to seize the city for his own. Knowing the fortress of le Cité was impenetrable, Charlemagne’s troops laid siege to starve the occupants out of le Cité. The siege continued for years and years with food stores in le Cité eventually running desperately low. Just when food supplies were nearly exhausted and it looked like a surrender of le Cité was the only option, Madam Carcas had the very last of the city’s grain force-fed into one of the remaining pigs. The pig was then thrown over the battlement down at the troops below. The pig hit the ground and burst open from being so over-stuffed with grain. Charlemagne’s troops despaired that even le Cité’s livestock was still being fed grain and the occupants had enough food that they could waste it by throwing surplus food at the troops. If after years of siege le Cité still had those kinds of food reserves, there was no hope of starving the city’s occupants out of the fortress. Charlemagne withdrew his troops and Madam Carcas taunted the troops by yelling, “Carcas te sonne!” or “Carcas is calling you!” In appreciation for saving le Cité, the town people changed the name of the town to “le Cité de Carcassonne.”
None of this story is historically true, but never let the truth get in the way of a great tale. Around 100 BCE le Cité was a Roman colony already known as Carcasum.
But the legend of Madam Carcas is a great story and maybe the origin of the phrase, “When pigs fly?”
Regardless of facts, today there is a sculpture of Madam Carcas welcoming visitors at the entrance of le Cité de Carcassonne.