A commission was sent in 1875 to negotiate a purchase.

Led by Senator William Allison of Iowa — and therefore called the Allison Commission — it met with Sioux leaders in September 1875.

The talks failed.

The Sioux were willing to discuss compensation for the right to mine gold in the Hills, but they were not willing to sell.

The price ranges the commission was authorized to offer were far below what Sioux leaders understood the hills to be worth, in the purely monetary terms the commission was applying.

The negotiations broke down.