In 1916–1917, Russian Academy of Sciences sent expedition to the occupied by Russian troops Trabzon, led by famous Byzantinist Feodor. I. Uspensky, in order to guard, register and describe local historic monuments and artifacts. One of the expedition’s important activities was collection and description of old manuscripts, collected and brought mostly into the main city mosque Ortahisar. Since the summer of 1917, this work had been carried out by the famous orientalist Agafangel E. Krymsky. The expedition collected about 32–48 tonnes of books, manuscripts, and various papers, including several Qur’ans of the late 19<sup>th</sup> century, literary works in Turkish, Arab and Persian languages, as well as numerous documents, helping to form a representative image of Trabzon’s socio-economic situation for the whole period of Turkish rule (15<sup>th</sup> – early 20<sup>th</sup> centuries). The expedition selected some manuscripts from the corpus of collected works and relocated them to Batumi and Tiflis before the retreat of Russian troupes. Not all the results of the expedition were published because of the conflicts of their scientific interests and the Civil War in Russia, when the contacts between the expedition members were lost. In the 1920<sup>th</sup> the Turkish government raised the question about the captured manuscripts, so they were returned in 1929 in exchange for the part of the property of Russian Archaeological Institute in Constantinople. Present research reveals that most of the manuscripts were successfully returned, while only some of them disappeared during the Civil War. New documents from various Russian and foreign archives based on the surviving correspondence and the drafts of letters help us to restore the chronology of those events. The fate of manuscripts from the times of their collection in 1916 to their description in 1917 and the return to the Turkish government is traced. Here are for the first time published some records of Agafangel E. Krymsky and his personal correspondence, as well as some relevant the correspondence of the People’s Commissariat for Foreign Affairs with the Academy of Sciences. The author also uses information from other unpublished sources, such as the memoirs of Trabzon city administrator Dr. Ya.  I. Kefeli.