The Cathar Crusade: Part V-The Fall of Simon de Montfort

The Cathar Crusade, a crusade against non-violent followers of a different form of Christianity, lasted from 1209 to 1229, and resulted in the conquest of the Toulouse region by the French king, the establishment of papal domination over the Christian church in Europe and the creation of the Papal Inquisition, basically the first secret police. Part V covers the efforts of Count Raymond of Toulouse to win the pope's support during the Fourth Lateran Council, the continuation of the crusade and the final defeat of Simon de Montfort.

Cast of Characters:
Simon de Montfort-earl of Leicester, viscount of Trencavel, leader of the crusade 
Raymond VI-Count of Toulouse
Raymond VII-Count Raymond's heir
Raymond-Roger-Count of Foix
Fulk-Bishop of Toulouse, member of the Cistercian Order
Innocent III-Pope
Honorius III-Pope, Innocent's successor 
Pietro of Benevento-papal legate
Betrand-cardinal of St. Paul and St. John, papal legate

Sources:
Kill Them All: Cathars and Carnage in the Albigensian Crusade-Sean McGlynn
Innocent III: Leader of Europe 1198-1216-Jane Sayers
Pope Innocent III and His Times-Joseph Clayton
The Popes: A History-John Julius Norwich
The Occitan War: A Military and Political History of the Albigensian Crusade, 1209-1218-Laurence W. Marvin
A Most Holy War: The Albigensian Crusade and the Battle for Christendom-Mark Gregory Pegg
The Perfect Heresy: The Life and Death of the Cathars-Stephen O'Shea
The Albigensian Crusade-Jonathan Sumption
The Medieval Crown of Aragon: A Short History-T. N. Bisson

Image Credit:
Pope Innocent III excommunicating the Albigensians (left). Massacre against the Albigensians by the Crusaders (right). 
By Chroniques de Saint-Denis - http://www.bl.uk/catalogues/illuminatedmanuscripts/ILLUMIN.ASP?Size=mid&IllID=43733, Public Domain, https://commons.wikimedia.org/w/index.php?curid=13305991