In the spring of 1858, Mullah Hussein Feiz-khanov, a Tatar language teacher at St. Petersburg University, was sent to Moscow to study at the Main Archive of the Ministry of Foreign Affairs. In the autumn of that year, he returned to St. Petersburg and brought with him a large collection of Crimean Tatar documents copied by him, relating to the period of relations between the former Crimean Khanate and Russia and Poland. These documents were published as a separate book, which is offered in distribution.