The article for the first time introduces into scientific discourse information about the unique archive of V.Rozov, Ukrainian researcher in the history of language, as well as literature, culture, philosophy. The uniqueness of the archive lies, firstly, in the value of works on historical linguistics and dialectology, secondly, in the development of topics “language – history – literature – cultureˮ in their interrelation, and thirdly, in the “new discoveryˮ of ideas of V. Rozov as one of the major linguists of the first half of the XX century and consideration of the prospects of his conclusions in modern linguistics. The archive contains the manuscripts of V.Rozov, which have not yet been systematically described and published, as well as printed materials. They open up to now a scientific heritage not appreciated sufficiently of the great Ukrainian linguist, who was only mentioned fragmentarily as a publisher of Ukrainian letters of the XIV-XV centuries. The archive impresses with the erudition of the linguist, his vocation in the works known in European linguistics, the profound knowledge of languages – Slavic and non-Slavic, and the scientific argumentation of the presentation. The languages of printed and handwritten works – Ukrainian, Russian, Serbian, among the most studied genres – letters of the XIV-XV centuries, as well as Ukrainian school drama. The study of the scientific heritage of V.Rozov needs to be presented in a series of articles, the first of which covers his teaching and scientific activities at the University of St.Volodymyr, the Kyiv period of his life. It was during this period that his interest in the issues of the Ukrainian literary language, dialectology, and linguistic source studies began, which in fact determined the main directions of scientific activity in subsequent periods of his life, although the factual material acquires a wider generalization and thoughtful comprehension.