Complex sentence: These he read before writing his report, which concluded with his proposed manual for American cavalry be adapted from existing Russian cavalry regulations and he also proposed a cavalry saddle that he clailmed was a modification of a Hungarian model used in the Prussian Service.
Split into simpler sentences: These he read before writing his report, which concluded with his proposed manual for American cavalry adapted from existing Russian cavalry regulations. He also proposed a cavalry saddle that he claimed was a modification of a Hungarian model used in the Prussian service.