In its 1868 treaty negotiated with Red Cloud, the US had pledged to hold the Black Hills inviolate as a permanent part of Sioux territory, not even to be entered by a white person. The Black Hills were the sacred center of the vast Sioux range, the place where they went to receive visions from the Great Spirit. In 1874, however, rumors emerged that there was gold in the Black Hills, and suddenly white miners were breaking the treaty to stake out claims in the hills. Instead of preserving its treaty obligations, the US sent in army divisions under Colonel George Custer (called “Long Hair” by the Sioux). By this time Red Cloud’s influence was waning—as an older chief now settled beside an Indian agency, his perspective did not carry as much weight with the younger generation of Sioux—and other leaders, like Sitting Bull and Crazy Horse, were becoming the dominant voices. In 1875, a set of US commissioners arrived to persuade the Sioux to give up the Black Hills, or at least to negotiate the mineral rights to the land. The Sioux stood firm in their refusal, so the commissioners returned to Washington and advised Congress to proceed with purchasing the land anyway.