Factual error: In the beginning of the film, a variety of different suitors are presented to Elizabeth. Amongst them are Eric XIV of Sweden, reportedly "still madly in love [with her]". Even though he was born the same year as Elizabeth; when this film takes place, in 1585, he had already been dead for 8 years.
Factual error: When one of Mary Stuart's correspondents writes her a note, he uses a quill and ink. Immediately following, he folds it up without sanding the wet ink. The writing would have been smeared so badly that it would be unreadable.