"Prince Vasili, a man of high rank and importance"

In Russian, the title 'prince' (kniaz) did not imply that the holder was an immediate member of the royal family, as it does in English. 'Prince' or 'princess' were titles used by the nobility to show they were descended from Rurik, the semi-legendary founder of Kievan Rus. The title could be inherited, or granted by the tsar.