Amos Bad Heart Bull, also known as Waŋblí Wapȟáha (Eagle Bonnet; c. 1868–1913), was a noted Oglala Lakota artist in what is called Ledger Art.
It is a style that adapts traditional Native American pictography to the new European medium of paper, and named for the accountants' ledger books, available from traders, used by the artists for their drawings and paintings.
Born about 1868 or 1869, Amos was the son of Bad Heart Bull (Tȟatȟáŋka Čhaŋtéšiča) and his wife Red Blanket (Tȟašína Lúta Wiŋ).
At the end of the Great Sioux War of 1876-77, the Bad Heart Bull family surrendered at the Red Cloud Agency on April 18, 1877, several weeks before Crazy Horse.
As a young man, Amos Bad Heart Bull showed interest in the history of the Oglala, and began to draw pictures depicting traditional lifeways and events.
In addition to classes in English and other topics of United States society, the fort's officials provided the men with drawing materials and ledger books for their work.
In the 1930s, she was contacted by Helen Blish, a graduate student from the University of Nebraska, who asked to study her brother's work for her master's thesis in art.
Through Alexander's admiration of Bad Heart Bull's work, and Alexander's position as thematic consultant for the construction of the Nebraska State Capitol, Bad Heart Bull is noted as a primary thematic design influence on the Nebraska State Capitol, particularly in its East Chamber (its original Senate chamber).
In the years since, scholars have come to view the Amos Bad Heart Bull images as a very important contribution to Lakota history and culture.