Józef Kowalewski, a founding father of Mongolian studies in Russia, stayed in Beijing from November 1830 until July 1831. He stayed with the Russian Ecclesiastical Mission and, being a Catholic himself, Kowalewski was very interested in the history and current state of Catholicism in China. In those years Catholicism in China faced severe persecution. All European missionaries were expelled from China with the exception of Bishop Gaetano Pirès Pereira, who was allowed to stay at the Russian Mission because of his old age. Kowalewski is said to have written a history of Catholicism in China which was destroyed by fire. However, unpublished diaries of Kowalewski, which survive in the Russian archives, contain much interesting information about Catholic cemeteries in Beijing, the life of Chinese converts, the Jesuit library and records of his talks with the last Catholic bishop.

An attempt to create a written Mongolian language based on the Cyrillic script is linked to the missionary activities of Archbishop Nil (1799-1874) among the Buryat Mongols. On his initiative, several Christian liturgical books were translated into Mongolian and printed in St. Petersburg. However, Nil and his assistants did not take into account the discrepancy between written and spoken Mongolian language and transcribed every letter of the Mongolian written language with corresponding Cyrillic letters and thus did no in any way make the texts closer to the spoken language.