The work gives a survey of contacts between the Papal See and Rus’; the chronological frames are from the eleventh till the fifteenth centuries. The first part of the book is on the Catholic expansion of the eleventh — thirteenth centuries. The second part is about the contacts with the Teutonic Order, and the situation after the Mongol invasion. The third part is a survey of the crisis of the papal politics related to Rus’ and the Moscovite State in the fourteenth and fifteenth centuries.

The contacts between the Holy See and Rus’ have been activated since the late tenth century, after the Christening of Rus’. The starting point of the research was connected with the beginning of the Great Schism; the final events were the Council of Florence, and the Fall of Byzantine. Noteworthy, the author analyzed the Papal relations not only with Rus’, but also with the Grand Duchy of Lithuania, a significant part of the population of which was Orthodox at that period, and the state authorities had their own ambitions of uniting lands of the former Kievan Rus’. For instance, R. analyzed a message from Pope John XXIII to Prince Gediminas of 1377 with its scholastic reasoning for the sake of the supremacy of the Roman Catholic Church.

The author put a special attention to the struggle against the Teutonic Order in the Baltic Region, setting it in the general context of the thirteenth century. He explained it with the Papal attempt to strengthen its positions as it was in the Latin Kingdom shaped after the conquering of Constantinople in 1204. He also described not only the obvious tendency of taking control over some new territories, but at some episodes of cooperation forced with the Mongol invasion.