Kurt Jonassohn and Karin Solveig Björnson describe the Albigensian Crusade as "the first ideological genocide".[156] Kurt Jonassohn and Frank Chalk (who together founded the Montreal Institute for Genocide and Human Rights Studies) include a detailed case study of the Albigensian Crusade in their genocide studies textbook The History and Sociology of Genocide: Analyses and Case Studies, authored by Strayer and Malise Ruthven.[157]