text: An epic poem called the "song" of this war was written in part by William of Tudela.
full_question: An epic poem called the "song" of this war was written in part by William of Tudela. One of the issues that led to this war was the consolamentum, a practice by which people could become "Perfects." After joining this war, Peter II of Aragon was killed at the Battle of Muret. During a siege in this war, a stone thrown from a mangonel killed the elder Simon de Montfort. During this war, Arnaud Amalric gave the command "Kill them all, for the Lord knows those that are His own" during the sack of Beziers. This war was sparked by the murder of papal legate Pierre de Castelnau, who was sent by Innocent III to investigate Raymond, the Count of Toulouse's allowance of a group in the Languedoc region. For 10 points, name this crusade which targeted the heretical Cathars in Southern France.
first_sentence: An epic poem called the "song" of this war was written in part by William of Tudela.
raw_answer: Albigensian Crusade [or Cathar Crusade until "Cathars" is read]