Why did chief Joseph lead the Nez Perce o a 1500 mile retreat westward?

Chief Joseph led the Nez Perce on a 1,500-mile retreat westward to escape the U.S. Army’s efforts to forcibly relocate his people to a reservation in Idaho. After a series of conflicts, including the U.S. government's encroachment on their lands and broken treaties, Chief Joseph sought to protect his tribe's way of life and secure their freedom. The retreat was marked by strategic maneuvers and attempts to reach Canada for refuge, ultimately highlighting the Nez Perce's resilience in the face of adversity.