The Moscow Commission, which conducted a systematic study of the Belarusian-Russian language border, unfortunately did not carry out similar research on the Belarusian-Ukrainian border. However, in light of the results of the Commission’s work, it became clear that both previous researchers – Rytykh and Karski – included only pure Belarusian dialects within the ethnographic boundaries of Belarus, leaving out all areas whose language betrayed some significant elements of the neighboring language. In preparing their maps, they completely disregarded ethnographic, historical, and other non-linguistic but important facts. As a result, Bryansk, Pskov, and part of Polesia ended up outside the ethnographic boundaries of Belarus, writes M. Ahniavida in the pages of the Munich newspaper “Batskaŭshchyna.” When it comes to Western Polesia, this mistake was noticed by the figures of the BNR and corrected on the Ethnographic Map of the Belarusian People’s Republic, published in 1919.
In M. Ahniavida’s assessment, only on the western segment of the southern border with Ukraine does the border of Belarus approximately coincide with the ethnographic boundary.
Hryhor Maksimovich (pseudonym Vitaut Tumash – On the Issue of the Belarusian Southern Ethnographic Border, in: “Zapisy,” No. 1 (5), New York 1954, pp. 18-24) notes that when determining the southern border of the Belarusian people’s settlement, starting from Rytykh’s maps from 1875 and Karski’s from 1904 and 1918, different authors present the ethnographic boundary differently, relying not on ethnographic but only on linguistic phenomena. Language is undoubtedly an important indicator, but, as follows from the work of the Moscow Dialectological Commission (N. N. Durnovo, N. N. Sokolov, D. N. Ushakov, Experience of the Dialectological Map of the Russian Language in Europe with an Appendix on Russian Dialectology. Proceedings of the Moscow Dialectological Commission, vol. V, Moscow 1915), there is no sharp linguistic boundary on the Belarusian-Ukrainian and Belarusian-Russian borders, but only a wide strip of transitional dialects. Therefore, when determining the boundary between peoples, in addition to linguistic features, it is necessary to take into account historical, anthropological, and ethnographic factors, notes R. Maksimovich (On the Issue of the Belarusian Southern Ethnographic Border, ibid., p. 18).
The southern ethnographic boundary was developed by the well-known Polish ethnographer Kazimierz Moszyński (K. Moszyński, Atlas of Folk Culture in Poland, 1936). The ethnographic boundary defined by him was considered by K. Moszyński to be a manifestation of an earlier geographical boundary.
“This, in his opinion, was to be an ethnographic phenomenon revealing the trace of the southwestern shore of those vast forests and thickets that once covered the northeastern part of the European continent” (R. Maksimovich, On the Issue of the Belarusian Southern Ethnographic Border, ibid., p. 20).
All ethnographic demarcations on K. Moszyński’s map run south of the Pripyat. If a median geometric line is drawn, it would approximately run along the southern border of Polesia with Volhynia, which is simultaneously the line of the old historical boundary from the times of the Grand Duchy of Lithuania, as well as the modern state border between Belarus and Ukraine (ibid., p. 22). Confirmation of this clear ethnographic Belarusian-Ukrainian boundary is also the way villages are constructed in Polesia and the Polesian folk patterns, as well as other local ethnographic features that are distinct from the Ukrainian and identical to the Belarusian (ibid., p. 23).
Meanwhile, some Ukrainian foreign organizations claim Belarusian southern lands, writes I. Kasyak in the pages of “Belarusian Thought” (Ukrainian Claims to Belarus, in: “Belarusian Thought,” No. 34, New York – South River 1989, pp. 32-37).
Thus, in the book Ukrainian Resistance, published by the Ukrainian Congress Committee of America in New York in 1949, there is a map of Ukraine signed by R. V. Halvin, where approximately half of the modern Brest region with the cities of Brest and Pinsk, as well as the southeastern and southwestern parts of the modern Gomel region with the cities of Starodub and Turov, are annexed to Ukraine (ibid., p. 32).
A similar part of the territory of Belarus was also annexed to Ukraine on an earlier map from 1930, created by V. Kubiovich and M. Kulytski in English, which was included in volume 2 of the encyclopedia Ukraine – A Concise Encyclopedia (prepared by Schevchenko Scientific Society, University of Toronto Press, Volume 2, 1971), published in Toronto in 1971. In volume 1 of this encyclopedia from 1963, there is a map of the Reichskommissariat of Ukraine from 1942, on which Brest and Gomel are annexed to the Reichskommissariat of Ukraine (I. Kasyak, Ukrainian Claims to Belarus, ibid., p. 33).