Anthony Hopes's classic tale turned into a classic adventure film with Ronald Coleman as the King and his commoner cousin who must masquerade as the king when he's first drugged into unconsciousness so he can't be crowned and later when the king is kidnapped. Its a rousing tale with a dynamite romance. It's been filmed numerous times and this one is probably the best. I put the Stewart Granger one a half step behind this one because James Mason isn't as evil as Douglas Fairbanks Jr as Rupert of Hentzau. You don't get casts better than this since it has Coleman, Madeline Carol, Fairbanks, David Niven, Raymond Massey, Mary Astor and C Aubrey Smith. You also don't get scripts better than this, the Granger version essentially used the same script so that as it ran I was quoting dialog and making my dad go "I thought you never saw this before". Possibly one of the best adventure films Hollywood ever made, I can't recommend it enough...