Sitting Bull in their land, as specified in the 1868 Treaty of Fort Laramie. It was alarmed at reports of Sioux depredations (encouraged by Sitting Bull). In November 1875, President Grant ordered all Sioux bands outside the Great Sioux Reservation to move onto the reservation, knowing full well that not all would comply. As of February 1, 1876, the Interior Department certified as "hostile" those bands who continued to live off the reservation. This certification allowed the military to pursue Sitting Bull and other Lakota bands as "hostiles". Based on tribal oral histories, historian Margot Liberty theorizes many Lakota bands allied with
Sitting Bull Later historians and ethnologists have refuted this concept of authority, as the Lakota society was highly decentralized. Lakota bands and their elders made individual decisions, including whether to wage war. Sitting Bull's band of Hunkpapa continued to attack migrating parties and forts in the late 1860s. When in 1871 the Northern Pacific Railway conducted a survey for a route across the northern plains directly through Hunkpapa lands, it encountered stiff Lakota resistance. The same railway people returned the following year accompanied by federal troops. Sitting Bull and the Hunkpapa attacked the survey party, which was forced to turn back. In