A year after his death in 1950, a book called When the Tree Flowered appeared about him, but it's not as well known as an earlier book which told the story of this man's life up to the Wounded Knee massacre.  
His letters to America, written on a trip to Europe in the 1880s, were published in the newspaper The Word Carrier.  After experiencing a vision of Thunder Beings as a child, he became a respected figure, but after being accused of devil-worship by Father Joseph Lindebner he broke with the religion of his youth and converted to Catholicism.  In 1908, the Jesuits sent him and Joseph Redwillow on a mission to the Arapaho, but the life of this "sixth grandfather" would change for good when he met a man he named Flaming Rainbow.  A year after his death in 1950, a book called When the Tree Flowered appeared about him, but it's not as well known as an earlier book which told the story of this man's life up to the Wounded Knee massacre.  FTP, name this holy man of the Oglala Sioux whose life was the subject of a book by John G. Neihardt.
His letters to America, written on a trip to Europe in the 1880s, were published in the newspaper The Word Carrier.  
Nicholas Black Elk (or: Hehaka Sapa)