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.