Mount Rushmore still disputed on the basis of the 1868 Treaty of Fort Laramie (see section "Controversy" below). Among American settlers, the peak was known variously as Cougar Mountain, Sugarloaf Mountain, Slaughterhouse Mountain, and Keystone Cliffs. It was named Mount Rushmore during a prospecting expedition by Charles Rushmore, David Swanzey (husband of Carrie Ingalls), and Bill Challis. Historian Doane Robinson conceived the idea for Mount Rushmore in 1923 to promote tourism in South Dakota. In 1924, Robinson persuaded sculptor Gutzon Borglum to travel to the Black Hills region to ensure the carving could be accomplished. Borglum had been involved in sculpting the
Mount Rushmore Confederate Memorial Carving, a massive bas-relief memorial to Confederate leaders on Stone Mountain in Georgia, but was in disagreement with the officials there. The original plan was to make the carvings in granite pillars known as the Needles. However, Borglum realized that the eroded Needles were too thin to support sculpting. He chose Mount Rushmore, a grander location, partly because it faced southeast and enjoyed maximum exposure to the sun. Borglum said upon seeing Mount Rushmore, "America will march along that skyline." Congress authorized the Mount Rushmore National Memorial Commission on March 3, 1925. Between October 4, 1927, and October