Factual error: After the snake swallows the dagger - it is able to curve its body beyond that which having the dagger inside would allow.
Continuity mistake: While storming the eastern gate of Alamut, Dastan climbs up onto a high beam with some rope. He then ties the rope around the beam and in one shot, the part of the rope that Dastan is holding onto is on the left hand side of the beam. The shot then changes to the right side of the beam and the rope has suddenly switched sides.





Chosen answer: Dastan was tricked into presenting a poisoned gown to King Sharaman during the celebration. The gown fatally burns him.
raywest ★