Complex sentence: Because the ghost is incapable of crossing this bridge, Ichabod assumes that he is safe; however, the Hessian throws his own severed head at Ichabod, knocking him from the back of his own horse and falling onto the road.
Split into simpler sentences: Because the ghost is incapable of crossing this bridge, Ichabod assumes that he is safe. However, the Hessian throws his own severed head at Ichabod, knocking him from the back of his own horse and onto the road.