text: Are you familiar with the Seige of Beziers? While the history was written by the victors, after killing all the inhabitants, Christian and Cathar, it became the origin of the phrase "Kill them all, God will know his own" attributed to the Papal Legate nominally in charge of the mercenary army authorized by the Pope.
  
  http://www.ledevoir.com/non-classe/30862/le-fin-mot-de-l-histoire-tuez-les-tous-dieu-reconnaitra-les-siens-arnaud-amaury