The Kyivan Rus Version of Ukrainian Genesis. Arguments For and Against

National history is the core of the formation of national consciousness, the strength of which determines the viability of the nation. The birth of the national history subject is one of its key problems, without whose solution the successful building of a modern Ukrainian nation is impossible. In addition to the three main versions of the origin of Ukrainians (Trypillia, early mediaeval, and late mediaeval), some Ukrainian researchers propose the so-called Kyivan Rus concept of Ukrainian genesis.The article presents a critical analysis of the Kyivan Rus concept of the birth of the Ukrainian nation. Vasyl Balushok, who has published two monographs touching the issue of the ethnogenesis of Ukrainians, is its most active supporter among modern domestic researchers. In them, the researcher examines in detail the main aspects of the Kyivan Rus version of the origin of Ukrainians. Therefore, the basis of the article is the analysis of two of his monographic studies, which provide a fairly complete picture of the current state of the problem of the Ukrainian ethnic group origin from Kyivan Rus.Balushok believes that the formation of the Ukrainian ethnos took place in Rus state and ended at the turn of the 12th and 13th centuries. The main shortcoming of V. Balushok's version of Ukrainaian genesis is the researcher's failure to recognise the first, tribal phase of the formation of Ruthenians-Ukrainians. It covers the entire early Middle Ages from the end of the 5th to the 10th centuries, when the Ukrainian ethnos consisted of related proto-Ukrainian tribes: Antes, Sklavens, Dulebs, Polans, Drevlians, Volhynians, Ulychis, Tivertsi, Croats. The latter consolidated into an aristocratic nation of Ruthenians-Ukrainians in the state of Rus during the 10th–13th centuries.The ethnogenesis of Ukrainians took place within the framework of the universal laws of the ethnohistorical development of the peoples of the middle part of Europe: Englishmen, Spaniards, Frenchmen, Romanians, Czechs, Poles, Serbs, Croats, Ruthenians-Ukrainians, etc. All of them went through three main phases of development: 1. The tribal period of the early Middle Ages (5th–9th centuries); 2. Aristocratic nations of the developed and late Middle Ages (10th–16th centuries); 3. Modern nations of the new and modern times (17th–21st centuries). V. Balushok's non-recognition of the tribal phase of Ukrainian genesis contradicts the specified universal laws of the development of the great ethnic groups of Europe.