(Musorgsky: Boris Godunov). Ten. A novice monk, Grigori hears from his mentor, Pimen, how the young Tsarevich Dimitri was murdered. He realizes he is the same age the Tsarevich would have been and determines to take his identity, defeat the present Tsar, Boris Godunov, and assume the throne of Russia. Created (1874) by Fyodor Komissarzhevsky.