American Horse the Younger gained influence during the turbulence of the Great Sioux War of 1876-1877. After news of the death of Chief American Horse the Elder at the Battle of Slim Buttes, Manishnee (Can not walk, or Played out) seized an opportunity and assumed the name "American Horse." American Horse the Younger was not related to American Horse the Elder, son of Old Chief Smoke. He was the son of Sitting Bear, leader of the True Oglalas, a band of Oglala opposed to the Smoke people In 1890, American Horse the Younger told Charles A. Eastman that he succeeded to the name and position of his uncle American Horse the Elder who was killed at Sim Buttes in 1876. Later, American Horse the Younger claimed that American Horse the Elder was not killed at Slim Buttes, but rather a minor chief Iron Plume or Iron Shield. He also claimed that he personally killed Captain William J. Fetterman with his war club in the Fetterman Fight during Red Cloud's War. As a result, the identities and accounts of American Horse the Elder and the American Horse the Younger have been blended by some historians. Like his great friend Crazy Horse, there are no known photographs or drawings of Chief American Horse the Elder. "The Oglalas seem incapable of clearing up the tangle."