Continuity mistake: All the castle windows on the outside of the castle are small squares yet from inside the rooms they're arched.
Continuity mistake: During the Treaty signing Merlin's cape collar goes up and down depending on the type of shot it is - close up the collar is up, distance the collar is down.
Continuity mistake: After Merlin drinks from the goblet he puts his empty right hand up to his face. However, when he collapses the goblet is shown falling out of his right hand.
