The nineteenth century saw the rapid expansion of American settlement across the western frontier. As American settlers trekked across the American continent, territorial conflicts between the settlers and Native Americans increased in number and intensity. These conflicts caused a frustrated U.S. government to create the reservation system in 1851. The purpose of this system was to keep Native Americans off the lands coveted by European American settlers and to control violence in the American West. By marginalizing Native Americans and forcing them onto sub-optimal lands, however, the government exacerbated tensions, leading to a series of bitter conflicts now collectively known as the Indian Wars. Eventually, the U.S. Army subdued the Native Americans and forced them onto reservations, where they were permitted to maintain their cultural traditions and some measure of political autonomy. Many Americans were unsatisfied with this outcome, however, and demanded that Native Americans be more aggressively assimilated into mainstream American society. The 1887 Dawes Act was an attempt by the U.S. Government to use legislation to coerce Native Americans into assimilating into European American society.