Medieval Eastern Europe... Rus' and Khazaria - neighborhood and irreconcilable enmity, which ended with the destruction of the Khazar Kaganate. How did they build relationships? Why did one country win, and the other lose, and after losing, disappear forever? One of the most mysterious and insoluble mysteries of our past. The best minds are struggling to solve it, but scientists have not agreed on what opinion of their colleagues should be considered generally accepted.