The historian of ancient Russian literature, the author of studies on the literature of modern times, the publisher of monuments of ancient Russian literature M.N. Speransky (1863-1938) paid much attention to the study of Russian folklore material, developed a methodology for its study and proposed its systematization. He convincingly presented the Cossack historical song with a special folklore genre, dedicating a special work to it and preparing for printing 27 most characteristic and vivid songs that reflect the history of the Cossacks. The article reveals for the first time the significance of the scientist’s work devoted to the historical Cossack song, which he described as the most important «stage in the development of the past song».
Key words: the study of folklore, the history of the Cossacks, historical song, scientific tradition, historiography, M.N. Speransky.