This law made 160 acre of lots of public land available to anyone twenty-one or older, who was an American citizen, or intended to become one regardless of race, sex, or other protected status. It was sold at $1.25 per acre and if they improved it for five straight years, the land was then free. Cheyenne Chief, Black Kettle, led his people to Sand Hills, Colorado wishing for peace. On November 29, 1864, John M. Chivington led his men on a violent killing spree. Black Kettle was spared, but was then killed four years later. This was known as the Chivington's Sand Creek Massacre. Later on, they were advised to kill all Native Americans on site, which was known as the "free fire zone". In 1875 a discovery of gold in the Black Hills Reservation gained the attention of American prospectors. General Phillip Sheridan persuaded President Ulysses S. Grant that the Native Americans should be forced off the land altogether. The government offered to buy the land, but they rejected the offer since this was where they were relocated to. This led to the government wanting to take over the land, however the Lakota Sioux Tribe defended them from taking it over. Within a year the Great Sioux War of 1876 to 1877 had begun. The three chiefs that were on the defensive side of this war were "Crazy Horse", "Sitting Bull", and "Rain In The