 In one scene, Navarre tells Philippe to ride his horse to Imperius  castle and slaps the horses rear to make it ride. However, the  first time the scene was filmed, Rutger Hauer (Navarre) slapped the  horse too hard and it rode over the hill and into the horizon. The  horse was too powerful for Matthew Broderick to stop and so all  everyone could do was sit and wait for him to come back.