According to its contents, the newly found manuscript, Cod. Athous Panteleemon. gr. 283, is of interest for the Russian church historians and the researchers of the cultural and literature relations between Athos and Russia, since the author and copyist of the book Jacob Neaskytiotes included hitherto unknown Greek translations of Rus’ian hagiographical and liturgical texts and other materials on Russian, Serbian, and Bulgarian history of Athos. The Codex comprised the Akolouthia for Rev. Antony the Ross (Service to Antonii of the Pecherskii monastery), his Life, the Service for Feodosii (Theodosios), the Hegoumenos of the Pecherskii Monastery, the Life of Mitrofan (Methrophanes) of Voronezh, and other works. The book dated from July 1848. The methods of palaeographic and codicological analysis allow the one to trace the history of the book. Textological methods lead the one to the conclusion of the Russian origin of the texts which became a milestone for the creation of Jacob Neaskytiotes’ fundamental corpus of the Athonias. The text of the Greek translation of the Russian hagiographic monument originates from the second Russian edition of the Life of Mitrofan of Voronezh. There the text is much enlarged and revised in comparison with the first edition of hagiographic materials of 1832, the year of canonization of Mitrofan in Russia.