Dear Cossack People, “whose” are you today? Russian? Turkish? Isn’t it time to slowly become Cossack? The history of the Cossacks remains little studied to this day. The reason for this is the lack of reliable materials, as well as the political factor of reluctance to recognize the Cossacks as a full-fledged people in multinational Russia. At the same time, documents from foreign archives make it possible to lift the veil of the historical past. The basis of the book was the “Don Archive,” which was taken out during the liberation of Prague and lay motionless for a long time in the State Archive of the Russian Federation.