As more and more wagon trains crossed the Great Plains and miners moved into present-day Colorado and Montana, the Oglala or Dakota Sioux Indians became increasingly belligerent toward the white trespassers on their hunting grounds. They constantly harrassed US Army units sent to build forts to protect Bozeman Trail, a shortcut from Fort Laramie in Wyoming to the gold mines in Montana. In 1866, the Sioux ambushed and slaughtered 83 soldiers ordered to rescue a besieged working party [i.e., Fetterman Massacre]. The Sioux were expert horsemen and sharp-shooters, and their tactics were to attack unexpectedly and then disappear. There were so many incidents of Indian raids and depredations [e.g., Wagon Box Fight] that the citizenry became aroused, and in 1867 the US Congress established an Indian Peace Commission to stop the fighting. The following year Chief Red Cloud (1822-1909) agreed to a peace treaty, the terms of which stipulated that the US Army abandon the forts on the Bozeman Trail and the trail itself. In turn, the Sioux would relinquish some of their territory and move to a reservation by 1876. all this was done, and the Sioux were relatively peaceful for several years.