The book traces the male-line descent of Muscovy's royal family not only from Rurik, but from a certain Prus, to whom his uncle, Emperor Augustus, gave the northern part of the world, which later came to be known as "Prussia".Soviet Historical Encyclopaedia These claims to imperial heritage are further shored up by the story of Monomakh's Cap, a purported imperial crown which Constantine IX Monomachos of Byzantium is supposed to have presented to his grandson, Vladimir Monomakh, and which was used at coronations in Muscovy.
