On February 18, 1861, six chiefs of the Southern Cheyenne and four of the Arapaho signed the Treaty of Fort Wise with the United States, at
Bent's New Fort at
Big Timbers near what is now
Lamar, Colorado, recently leased by the U.S. Government and renamed
Fort Wise, in which they ceded to the United States most of the lands designated to them by the Fort Laramie treaty. Some bands of Cheyenne including the
Dog Soldiers, a militaristic band of Cheyennes and
Lakotas that had evolved beginning in the 1830s, were angry at those chiefs who had signed the treaty, disavowing the treaty and refusing to abide by its constraints. They continued to live and hunt in the
bison-rich lands of eastern Colorado and western Kansas, becoming increasingly belligerent over the tide of white immigration across their lands, particularly in the Smoky Hill River country of Kansas, along which whites had opened a new trail to the gold fields. Cheyennes opposed to the treaty said that it had been signed by a small minority of the chiefs without the consent or approval of the rest of the tribe, that the signatories had not understood what they signed, and that they had been bribed to sign by a large distribution of gifts. The whites, however, claimed the treaty was a "solemn obligation" and considered that those Indians who refused to abide by it were hostile and planning a war. ==Colorado War and Sand Creek Massacre==