High Middle Ages in Kyivan Rus' left us a splendor of sources which shed the light to its Christian spiritual practices, worldviews and theological ideas. These sources are various, including chronicles, lives of saints, testaments, sermons, travel diaries, inscriptions on the walls of old churches, and so forth. Contradictory to the theory of modern nations they testify to the existence of imagined proto-national communities based on common language and religion, not only on dynastic loyalty. They also reveal the spoken language. Moreover, they show religious convictions and individual piety of the age. The history of Kiev Rus' or Kyivan Rus' became a battle between Russian imperial historical narrative, claiming it to be the cradle of triune nation, and Ukrainian historiography, stating that Kyiv was always Ukrainian. Unfortunately, the first narrative is still firmly dominant amongst theological academia, who inherited it from the Russian Orthodox White emigration. Even in the 21st century, the whole medieval period of Kyivan state is automatically attributed to Russia, while Ukrainian language and culture are regarded to be the fruit of Polish influences. In my presentation, I'm not going to deal intensively with historiographic debates. Instead, I would like to give the voice to medieval Kyivans themselves - to trace their concerns and ideas from pages of the Primary Chronicle by Nestor, the Testament of Volodymyr Monomakh to Children, the Sermon on Law and Grace by Hilarion, metropolitan of Kyiv, and other primary sources. This classics, however, helps to grasp their spiritual, national and political imagination. It also posts a question whether a Kyiv theological tradition emerged in that era and, if so, what features it had.