Original: The Albigensian Crusade or Cathar Crusade (1209 1229) was a 20-year military campaign initiated by the Catholic Church to eliminate the Cathar heresy in Languedoc.
Simplified: The Albigensian Crusade or Cathar Crusade (1209 - 1229) was a 20-year military campaign. It was initiated by the Roman Catholic Church to eliminate the Cathar heresy in Languedoc.