Complex sentence: In it, Long Lance claimed that he had been born a Blackfoot in Montana's Sweetgrass Hills, and that he had been wounded eight times in the Great War and been promoted to the rank of captain.
Split into simpler sentences: In it, Long Lance claimed to have been born a Blackfoot in Montana's Sweetgrass Hills. He said that he had been wounded eight times in the Great War and been promoted to the rank of captain.