Conflict between American settlers and Native Americans arose from the westward expansion of the United States in search of land and resources. As settlers moved west, they negotiated treaties to remove Native Americans from their lands, often by force, pushing tribes onto reservations over the next 30 years through wars that killed hundreds. Attempts were also made to assimilate Native American cultures, including through boarding schools, but many Native Americans resisted giving up their traditions and way of life. The conflicts and policies of the U.S. government nearly destroyed many Native American societies.