"Kill them all. For God knows His own." Today is the 800th anniversary of the massacre of the inhabitants of the town of Beziers in Languedoc, in the south of France, known by the Romans as Gallia Narbonensis. Beziers was the first town to be sacked in the Albigensian Crusades to extirpate the Christian heresy of Catharism, which flourished in Languedoc. The Albigensian Crusades represented the initial application in Europe of religious warfare sanctioned by the resurgent medieval Papacy, and led directly to the institution of the Inquisition and rise of the Dominican Order.