November 29 marked the 150th anniversary of one of the most violent episodes in American history—a massacre of Native Americans so horrific that it prompted two Congressional investigations; forced the resignation of two leaders—Colonel John M. Chivington and the governor of Colorado Territory, John Evans—and launched years of battle with the Plains Indians following the Civil War.

The Sand Creek Massacre of 1864 was the topic of a November presentation by Ned Blackhawk at the Radcliffe Institute, held in partnership with the Harvard University Native American Program. Blackhawk, a Western Shoshone, is a professor of history, American studies, and ethnicity, race, and migration at Yale University, where he is also faculty coordinator of the Yale Group for the Study of Native America.

In his introduction of Blackhawk, Daniel Carpenter, the director of the social sciences program in Radcliffe’s Academic Ventures and the Allie S. Freed Professor of Government in Harvard’s Faculty of Arts and Sciences, said, “A university is a conversation—a highly bureaucratized conversation, to be sure—but a vital dialogue nonetheless. And it is vital to the future of Harvard—and in deep consistency with Harvard’s Native past—that the voice of Native American and indigenous people be amplified and strengthened.”

On the morning of the Sand Creek Massacre, Chief Black Kettle—considered the leading peace chief of his day—was camped in an isolated area of southeastern Colorado Territory with about 700 Cheyenne and Arapahoe Indians. The residents that morning were mainly women and children and older men. The young men were off hunting buffalo, the main source of food for the Cheyenne and Arapaho, and the Sand Creek area had none.

Colonel Chivington, a bloodthirsty Methodist minister—“the mad preacher,” the writer Larry McMurtry calls him—approached Black Kettle’s camp, ignoring the flags that waved from the chief’s tipi. Black Kettle had hoisted a United States flag that a former commissioner of Indian Affairs had given him; it flew above a white flag of peace that he had been told would alert the soldiers that his camp was peaceful...