Kievan Rus' vs Rus

Kievan Rus'

Rus

name
  • The medieval East Slavic state established by these same warrior merchants in the 9th century, whose capital was first in Novgorod and then in Kiev; Kievan Rus. 

  • The nation of Russia, especially in a transcendent or romantic sense referring to the history and culture of the country. 

  • A people made up of Scandinavian warrior merchants who travelled Eastern European river-roads from the eighth century, and whose settlements around Novgorod, Kiev and the Volga and Dnieper gave rise to the Russian principalities. 

  • Any of the medieval East Slavic principalities ruled by this class, especially Kievan Rus. 

noun
  • A person from Rus. 

How often have the words Kievan Rus' and Rus occurred in a corpus of books? (source: Google Ngram Viewer )