The article considers the relations between Nikolay Ivanovich Kareev (1850-1931) and Vladimir Ivanovich Lamansky (1833-1914). The author notes that the fact that N. I. Kareev moved from Warsaw University to St. Petersburg University was considerably determined by V. I. Lamansky who at that time served as a dean of historical-philological faculty of the University. In spite of the inconformity in their worldviews and philosophical inclinations (V. I. Lamansky was a convinced Slavophile, while N. I. Kareev was a Westernizer), there was respect between two scholars. Apart from the University, N.I. Kareev and V.I. Lamansky had relations in the Literary Foundation. N.I. Kareev's letters found in the St. Petersburg branch of the Archive of the Russian Academy of Sciences allows us to reconstruct the historical details of V.I. Lamansky's work on the entry «Slavs» for the «Brockhaus and Efron Encyclopedic Dictionary» which was edited N.I. Kareev; the circumstances how V. I. Lamansky became acquainted with Ukrainian h