The article analyses the ideas about truth as a socio-legal and religious-moral ideal of Ancient Rus, and aims to systematize these ideas and identify their evolution. To this end, Old Russian written sources were studied, where one can find ideas voiced by an author of a specific source or the people who are in the narrative, concerning the concept of “truth”, which, of course, was ambiguous. Mentions of “truth” were identified, the context of the usage of this word in a historical document and its semantic load were analyzed. The next step was to determine common themes within which the sources referred to the “truth”, as well as coinciding views on this concept (if any). Based on the results of the study, an attempt was made to reconstruct some typical ideas about “truth” inherent in the era of Ancient Rus. The author of the article concludes that the Christian worldview paradigm almost completely emasculates the idea of justice as the inevitable retribution for deserts: on the contrary, within the framework of this paradigm, the belief prevails that offenders should be forgiven, not punished, and good deeds should be done just like that, unselfishly, and not for an award; God can repay the criminals justly, but he can also send down misfortunes to the righteous without any reason, only for the sake of testing or even for the sins of other people. The main goal is to lead a person to salvation; at the Last Judgment, God will evaluate not every specific deed, but the whole earthly life of a person and its results. This understanding of “truth” implies a paramount orientation towards life after death, and not towards earthly life. The study aims to fill the gap related to the study of the Old Russian worldview, since during the period under consideration, no purely philosophical treatises were created in Russia, and the researcher has to identify certain abstract ideas through contextual analysis and synthesis of individual statements or with the help of indirect references in various sources.