Investigation of the development of the Cathar heresy in south-west France, looking at how and why its growth differed across the regions. The medieval county of Quercy in Languedoc lay between the Dordogne and the Toulousain in south-west France; it played a significant role in the history of Catharism, of the Albigensian crusade launched against the heresy in 1209, and of the subsequent inquisition. Although Cathars had come to dominate religious...