Continuity mistake: In the scene in the woods where Tolstoy signs away the rights to his writings, the buttons on Valentin Fyodorovich Bulgakov's shirt collar are on the left side of his neck until the last shot, where the buttons have moved to the right side of his neck. (01:05:05 - 01:07:15)
Factual error: In the dinner scene with Helen Mirren and James MacAvoy, she was playing a gramophone recording of "Un Bel Di" from 'Madame Butterfly,' and the year was 1910. The opera was not recorded until much later.