Gold discoveries in Colorado in 1858 brought another rush of settlers into the heart of Cheyenne and Arapaho territory.

The United States renegotiated the treaty, reducing the recognized territories.

More settlers came.

Conflicts increased.

And then, on November 29, 1864, at Sand Creek in what is now Colorado, Colonel John Chivington led seven hundred Colorado volunteers in a dawn attack on a peaceful Cheyenne and Arapaho encampment flying both an American flag and a white flag of surrender.

The camp was led by Chief Black Kettle, who had been explicitly told that he and his people were under the protection of the U.S. government.

The soldiers killed and mutilated between 150 and 200 people — the majority of them women, children, and elders.

Chivington’s men returned to Denver with body parts as trophies and received a public welcome from a significant portion of the city’s population.

The Sand Creek Massacre transformed the relationship between the Northern Cheyenne and the United States permanently.

Before Sand Creek, there were Cheyenne leaders who counseled negotiation, accommodation, the exploration of a path toward coexistence.