The article discusses a controversial issue of authorship of “The Story of Innocent Imprisonment of the Closest Boyar Artemon Sergeyevich Matveyev…”, created no later than 1728 and served as one of the main sources on the history of political struggle during the reign of Tsar Feodor Alekseyevich, from 1682 and in the years that followed. Most researchers attribute this complex text to Andrei Matveyev, a boyar’s son and noted statesman, who was a closest associate of Peter I and the first Ambassador and Permanent Representative of Russia to European states. According to other researchers, priest V. Cherntsov who had been living with A. Matveyev during his exile, can also be considered as the author. However, the analysis of subject-object relations within the text of the author’s “Announcement of the Return of the Closest Boyar <...> and His Death” included in the “Story”, as well as many specific details and noticeable stylistic and compositional differences from a significant part of the earlier “Notes” on the Streltsy riots written by A. A. Matveyev, allow to consider Ivan Poborsky, a native of the Orthodox Polotsk gentry, to be most likely author-compiler of the entire “Story”. Ivan Poborsky accompanied boyar Matveyev’s family during their exile and disgrace, being Andrei’s teacher of Latin and Polish (introducing Philosophy to him also) and performing all the functions of a secretary for his patron, after whose death (during the Moscow uprising of 1682) Ivan Poborsky became a priest. He remained close to Count Matveyev at the time of writing “The Story”, apparently serving as a priest at his house churches in both capitals, which may explain, for example, his good awareness of Matveyev’s “Notes”. The authorship of I. Poborsky, the stylistic and terminological specifics of the “Story”, as well as the arguments of this text, are well correlated with Poborsky’s priesthood and his biographical data, reconstructed on the basis of scientific literature, folklore and documentary sources and personal notes. It was possible that he was taught by the famous Simeon of Polotsk before the latter moved to Moscow. Poborsky served in the house church of Tsar Ivan Alekseyevich and made acquaintance with the author of “The Russian Grammar” in Latin, published in Oxford in 1696 - Henrici W. Ludolfi, who had come to Russia at that time. Then Father Ioann was appointed priest of the Great Embassy of 1697-1698, leading the first Russian mission abroad. He visited several European countries with the embassy. In addition to his spiritual ministry, I. Poborsky took part in diplomatic activities: on a call of Peter the Great he went from Holland to England and translated important documents to the Emperor.