“Walter Map, a cleric in the court of England’s Henry II and perhaps the author of the Grand Saint Graal (written circa 1189), relates that while there were no “heretics” in Brittany, by contrast there were many in Anjou, and that they were numerous in Burgundy and Aquitania (and consequently in Provence and Languedoc).
Caesarius von Heisterbach explains that the “Albigensian heresy” spread with such intensity that it had converts in almost a thousand towns, and if it had not been obliterated with blood and fire, it would have taken over all of Europe.
A historian belonging to the order of the Minorites cites it, together with Jews, pagans, Muslims, and German emperors, as the five great enemies of Rome.
Regarding their doctrine, the “Albigenses” (who shared only their name with Albi, a town in southern France) belonged to two different heretical sects. The best known were the Waldenses (founded by a merchant from Lyon named Peter Waldo), who spread throughout Western Europe in an incredibly short period of time. The second were the Cathars (from the Greek katharos = pure, and the origin of the German word ketzer or heretic). They could easily be called the Mahatma Gandhis of the West in the Middle Ages. Bent over their looms, they pondered whether “the spirit of the world weaves the living suit of divinity in the creaking loom of time.” This explains why they were also called the “weavers.”
Considering that this book does not pretend to describe the histories of all these sects, I will only refer to the Waldenses when they appear within the framework of my investigations. My work is centered on the study of the Cathars and their mysteries.”
From: Otto Rahn, The Crusade Against the Grail, pp. 16.