Which treaty was broken when gold was found in South Dakota

The Treaty of Fort Laramie (1868) was broken when gold was found in the Black Hills region of South Dakota. The treaty had guaranteed this land as part of the Great Sioux Reservation and protected it from settlement and mining. However, with the discovery of gold, non-native settlers flocked to the area, resulting in the violation of the treaty and subsequent conflicts between the United States government and Native American tribes, particularly the Sioux.