 Well, Colonel, on 25 June 1876, Native American forces led by Chiefs Crazy Horse and Sitting Bull defeated the Army troops of Lieutenant Colonel George Custer in a bloody battle near southern Montana's Little Bighorn River. In 1875, after gold was discovered in South Dakota, our Army ignored previous treaty agreements and invaded the region. This led many Sioux and Cheyenne tribesmen to leave their reservations and join Sitting Bull and Crazy Horse.