The library has had manuscripts written in Slavic languages since the 1800s. Manuscripts were received as donations particularly after the fire of Turku. The collection contains valuable ecclesiastical manuscripts from the 17th–19th centuries, letter collection and historical manuscripts. In addition, the collection includes private archives written primarily in Russian. The private archives are typically archives of Russians resident in Finland or Russian associations functioning in Finland. The collection has been created in conjunction with the Slavonic Library from where it was moved to the Manuscripts Collection in late-1990s.