PROBLEMS OF THE BALTIC-SLAVIC LINGUISTIC UNITY AND ANCIENT PRUSSIAN LANGUAGE IN THE SCIENTIFIC

The aim of the research is to analyze the methodological aspects of the use of V. Petrov's Baltic languages and their archaic structures for the reconstruction of the pre-written stages of the Slavic (Ukrainian first of all) ethnogenesis. The research methodology is based on the principles of historicism, systemicity, science, interdisciplinary. The following general-historical methods have been used: historiographical analysis, historical-genetic, terminological analysis, comparative, typological. The authors adhere to the civilizational approach and principles of cultural and intellectual history. The scientific novelty of the basis of a wide range of published and unpublished researches of V. Petrov on historiography, ethnogenesis, linguistics, archaeology, onomastics, the contribution of the scientist to the study of the Balto-Slavic community and the ancient Prussian language has been described.Conclusions. Many years of polydisciplinary research of V. Petrov from the Balto-Slavic language and historical connections became an important component of the proposed reconstruction of the ethnogenetic processes by the scientists in the ancient history of Ukraine («The ethnogenesis of the Slavs» (1972)).V. Petrov’s «Theory of the epochs» went beyond the tenets of the formation approach. It allowed us to consider the process of ethnogenesis as discrete, which has its own features within a self-sufficient era. The isolation of the Baltic element in the language of the Scythians and the advancement of the scientific theory of the existence of the Balto-Slavic linguistic community allowed the researcher to trace the connection between the Scythian age and the historical Slavs. Instead, in the theory of Slavic ethnogenesis of V. Petrov there was no place for the concept of «the united ancient Russian nationality», which was actively imposed by the official Soviet science.Many of V. Petrov’s conclusions of different degrees of generalization have been refuted now. However, the methodological approaches retain some research potential. The results of V. Petrov's study of the Prussian language require a further analysis of linguists