The first human activity on the site where the Cité now stands dates back to the VIth century before J.C. 300 for J.C. the Gauls subjugated the Iberians in Languedoc. 122 for J.C. the Romans conquered Provence and Languedoc and built a fortress called Carcaso. The region remained occupied until the middle of the 5th century. After the Visigoths occupied Spain and the Languedoc, they held the Cité from 460 to the year 725. In the year 725, the Cité is taken by the Saracens. In 759 they are defeated by Pépin le Bref, King of the Franks. After Charlemagne's death, the empire fell apart. From 1082 to 1209, the city experienced a period of development and prosperity.
The Viscount of Carcassonne (1194-1209), tolerated and protected the followers of Catharism in his territory. He therefore undergoes the first attack of the crusade, at the behest of Pope Innocent III. In 1209 after 2 weeks of siege, the viscount surrenders. His estates and the Cité are handed over to the military leader of the crusade. Later in 1224, all this is handed over to the French king, Philippe II (1165-1223).
The entry of the Cité into the royal jurisdiction led to a considerable upheaval. During the successive reigns of Louis IX, Philippe Le Hardi and Philippe Le Bel, the Cité takes on its current form and confirms its role as a royal bastion.
Due to the use of new fighting techniques and especially the shifting of the border between France and Spain in 1659, the Cité loses its defensive role and is increasingly neglected. In the 18th century, not much remains of the Cité, but thanks to the initiative of Jean-Pierre Cros-Mayrevieille, Mérimée, and the architect Viollet-le-Duc, the Cité has been preserved from demolition plans. As a result, thousands of people can now visit the most complete and authentic fortified city in Europe.