Petro Kalnyshevsky (1691-1803) entered the history of Ukraine as the last kish ataman of the Zaporoz’ka Sich, a talented military leader, a diplomat, an economist and a philanthropist. Personality of P. Kalnyshevsky causes heated debate until this time, despite a significant number of works (over 1650) devoted to the study of the important milestones of his life and activities. Among the masses of various topics associated with P. Kalnyshevsky, which arise periodically, is the military activity and martial art of the Zaporozhian leader, through the prism of the history of Nova Sich and the Russian-Turkish wars of the eighteenth century. The analysis of the status of the study of the figure of the Cossack ataman of the Zaporoz’n Sich P. Kalnyshevsky at the end of the XVIII – early XX centuries has shown unequal interest in this problem and ambiguous attitude towards it. We must pay tribute to the fact that it was the historical researches of the specified period that formed the basis for further objective research on the history of New Sich and the direct activities of P. Kalnyshevsky. The military activities of P. Kalnyshevsky began to be highlighted in the writings of the first historians of the Cossacks and continue to cause a research interest until nowadays. Nevertheless, there are no special studies on the identified issues in Ukrainian historiography. This issue was considered and continues to attract the attention of historians only in the context of studying the history of the Cossacks in general, or the life and activities of P. Kalnyshevsky. The historiographical analysis of the works related to the military activity of the Cossack ataman P. Kalnyshevsky made it possible to identify certain features and stages of the study of this problem. This issue didn’t attract the attention of scientists for a long time, and the available information concerned mainly the military service of the Zaporozhians during the Russo-Turkish wars. Thus, at the time of the XVIII century, we encounter small references that cover the military service of the Sich Cossacks. They are devoid of objectivity and permeated with a negative attitude towards the Cossacks, which shows the undeniable influence of imperial ideology on scientific research. There are observed some changes in the problem that we find out in the works of the second half of the nineteenth and early twentieth centuries. Historians of this era sought to deeper and more objective clarification of the issue. They used archival materials in their studies. However, the source base was provided without its critical analysis.