The Albigensian Crusade or Cathar Crusade (1209–1229) was a 20-year military campaign initiated by the Roman Catholic Church to eliminate the Cathar heresy in Languedoc. The Crusade was prosecuted primarily by the French and promptly took on a political flavour, resulting in not only a significant reduction in the number of practicing Cathars but also a realignment of Occitania, bringing it into the sphere of the French crown and diminishing t...