Which medieval Christian movement in southern France was targeted by the Albigensian Crusade?

The story behind the answer

Launched by Pope Innocent III in 1209, the Albigensian Crusade targeted a dualist movement flourishing in Languedoc (southern France), especially around Albi—hence the crusade’s name. Followers rejected the authority of the Catholic hierarchy, sacraments, and the material world, promoting an austere spirituality led by “Perfects.” Their popularity among local nobles threatened both church orthodoxy and Capetian influence.

The campaign turned into a brutal war of conquest: infamous massacres at Béziers and sieges like Carcassonne punctuated a conflict that lasted until 1229. Its aftermath reshaped the region—strengthening French royal power, curbing Occitan autonomy, and helping establish the papal Inquisition under the Dominicans. For contrast, the Waldensians were active in the Alps, while Bogomils and Paulicians were primarily Balkan and Byzantine movements.