Complex sentence: After the end of Great Sioux War in 1877, the Lakota people were impoverished, harassed and confined to reservations... many believed that Native Americans were a vanishing race whose only hope for survival was rapid cultural transformation.
Split into simpler sentences: After the end of Great Sioux War in 1877, the Lakota people were impoverished, harassed and confined to a reservation. At the time, many people believed Native Americans were a vanishing race whose only hope for survival was rapid cultural transformation.