Both Patrick Stewart (Lenin) and Freddie Jones (Witte) appeared in David Lynch's 1984 adaptation of Dune. Stewart played Gurney Halleck and Jones played Thufir Hawat.
Patrick Stewart is best known for playing Captain Picard in Star Trek: The Next Generation. Tony Jay (Tsar Alexander III) appeared that show's fifth season episode Cost of Living.
This episode takes place in 1894.