The attention of modern scientists to studying processes of cognitive activity reflection of the person in language becomes more and more permanent. Addressing the most ancient texts allows to observe the Russian culture behind evolution of key concepts. In article conceptual ideas of goodare investigated in outlook of the Russian Middle Ages. As material the texts of the chronicles which most fully reflect a condition of Russian of that time are used. The concept good is considered as the key ethical category developed in earlytimes. The analysis of the contextual representation use of a concept allows to observe good in articles of various contents behind evolution of good ideas in consciousness of the Russian people. Use of a semantic-cognitive analysis method has allowed to reveal features of reflection of a good concept in language consciousness of the Middle Ages person, and functional and semantic features of the lexemes connected with a good concept have been defined by descriptive and analytical method. As a result of research the conclusion has been drawn on gradual transition from perception of this concept as manifestations of will of the highest essence, God to understanding of human nature of good that is connected with changes in culture. Various aspects of understanding good in language consciousness of our ancestors, the most significant of which were ethical, aesthetic and social, are defined. The pragmatical orientation of ideas of the good understood as state of nature, favorable for the person or society is emphasized. The key language units serving for the nomination of the studied concept are revealed, their semantic, grammatical and syntactic features are characterized. Compound words with the first part good and benefit are revealed and analyzed
