One of the best historical films out there. It is extremely historically accurate, as much of the actors are unpaid reenactors, who agreed to act in the film as long as it was historically accurate. The reenactors even supplied the film with the cannons you see.
If the film took to many creative liberties with the story, the reenactors would not want to participate in a film that was not historically accurate. So as a result, the people making the film were forced to make it as accurate as possible, which leads to a great historical film.
It is not just historically accurate, it is very intense and the action scenes are just amazing. It is a long movie, but it is totally worth watching towards the end.