The article introduces a previously unknown text of the Genealogy of Russian Sovereigns from the collections of the Department of Manuscripts of the Russian National Library, which contains the engraving program of A. F. Zubov’s “Portrait of Catherine I surrounded by medallions with portraits of Russian princes and tsars” of 1725. It also reveals the source of this “Genealogy” in the form of a historical and genealogical introduction to the anonymous “History of Peter the Great”, in which Peter is presented the “fifty-sixth” ruler of Russia descending from Rurik. The process of textological research has enabled to establish a connection between these sources and the “Genealogy of Russian Sovereigns” compiled by Feofan Prokopovich, which contained 34 signature texts for P. Pikart’s engraving “Peter I in the genealogy”. The results of the study allow us to attribute both discovered monuments to Feofan Prokopovich. The research also defines that one of the most important means of legitimizing the power of a female ruler was the likening of Empress Catherine to Grand Duchess Olga. As a result of the study of the anonymous “History of Peter the Great”, a number of works by Feofan Prokopovich have been identified in its text. An examination of the lists of the anonymous history of Peter in the collections of the National Library of Russia as well as comparison between these texts and the works of Feofan Prokopovich enable to substantiate the hypothesis about the authorship of F. Prokopovich regarding this compilation history.