If you watch the showdown with Bois-Guilbert closely, Ivanhoe slices two separate shields. After Bois-Guilbert loses the first, it looks as if he is quickly handed one from a nearby guard - you see him raising the second one up from foot-level. This second shield is subsequently damaged as well, in much the same way as the first. These shots are over in a matter of seconds, so it's easy to miss.
That being said, there's no end of other goofs to be seen. The tournament scenes in second hour of the movie are full of them. Most glaring is the reference to a joust between Bois-Guilbert and one of the Saxons lords, "Bois-Guilbert met his with such pleasing... finality," that is never observed, for example.
That being said, there's no end of other goofs to be seen. The tournament scenes in second hour of the movie are full of them. Most glaring is the reference to a joust between Bois-Guilbert and one of the Saxons lords, "Bois-Guilbert met his with such pleasing... finality," that is never observed, for example.