Internecine wars were a characteristic phenomenon of the Middle Ages: in this way representatives of the ruling dynasties defended their interests. The most famous among the dynastic tragedies of this era is the story of Saints Boris and Gleb, killed by their elder brother, Prince Svyatopolk. But there were other fratricidal conflicts between the Russian princes...Historian Dmitry Aleksandrovich Borovkov analyzes ancient Russian and Scandinavian sources, trying to compare facts, recreate the political situation of that time, consider different opinions - and, perhaps, get closer to the truth, who was right and who was wrong in those long-standing civil strife. Similar conflicts in the countries of Scandinavia and the “barbarian kingdoms” of early medieval Europe are also examined.