Jirina Jirásková was originally considered for the part of Ofka, eventually played by Slávka Budínová.
Jan Werich was originally considered for the part of purkrabí, eventually played by Jaroslav Marvan.
Jana Brejchova (playing Emperor's wife) was very anxious about horses. In the scene, when arriving to Karlstejn, her horse was led by a guy, plus the animal was carefully selected as the calmest from the lot.