The book covers the period from the eve of the First Crusade against the Albigensians in 1209 to the death of the initiator of the campaign of Pope Innocent III in 1216. In detail, with many details, the author examines the dramatic and bloody events of the war with heretics in the south of France in the first quarter of the XIII century, which influenced the entire further course of European history. The text is printed according to the publication: N.A. Osokin. History of the Albigensians and their time. Kazan, 1869-1872.