Not a formal written guarantee — the terms were ambiguous enough to allow Evans and Chivington to deny that any specific promise had been made.

But an understanding sufficiently concrete that Black Kettle and the other chiefs believed they were taking the actions necessary to secure their people’s safety.

When the congressional investigation examined the Camp Weld council, the investigators concluded that the chiefs had acted in good faith — that they had done what American officials had told them to do, and that the attack at Sand Creek therefore constituted a betrayal of specific commitments, however those commitments had been expressed.

Chivington disputed this characterization.