ENThe article is devoted to the origin of the term “Ruthenia” and “Ruthenian”, the process of developing the “Ruthenian nation” interrupted by the Union of Lublin, which divided the area inhabited by the Ruthenians into Lithuania and the Crown, the collapse of the Ruthenian religious-ethnic community and shaping two nations within it limits – Ukrainian and Belarusian, as well as the remains of the previous Ruthenian awareness in the peripheries of such developed nations: Lemkos, Boikos, Zakarpattia Ruthenians and Slovakian Ruthenians, as well as the awareness of many Podlasie Orthodox inhabitants. At the beginning of its expansion, the Grand Duchy of Lithuania was of a Ruthenian nature. 80% of this vast country’s inhabitants were Ruthenians. They also prevailed among the elites. Moreover, Ruthenian was the country’s official language. The elites were gradually polonized converting themselves into Catholicism. Nevertheless, they remained closely related to the ethnic tradition of this area participating in the creation of national ideas. It is particularly apparent in Belarus, where the authors of Belarusian contemporary literary language and Belarusian literature were writers and artists derived just from these communities. I would like to depict in this article a role of a civilization (mainly religion), ethnic (mainly language) and political factors (the state) in shaping the present ethnic-national map within this “post-Ruthenian” area.