For many years after Little Big Horn, Black Elk was a shaman, a pagan "medicine man" and cleric. When Black Elk was in his forties, he was called to the bedside of an apparently dying elderly Lakota warrior and tried to revive him to no avail. At that point, a Roman Catholic missionary priest arrived, baptized the old man, administered the sacraments to him and the man revived. This occurred in around 1905. Black Elk was devastated and, perhaps, humiliated. Nonetheless, he then asked the priest to baptize him and Black Elk spent the rest of his very long life as a Roman Catholic lay missionary to the Lakota, dying in about 1950 at an age estimated to be 87.
I have heard but cannot confirm that he died trying to walk to Mass in a blizzard.
Nienstadt deserves maximum skepticism as an historian. He apparently went into his work with the old noble savage stereotype of Black Elk and would pay no heed to (Nicholas) Black Elk's Catholicism.
He undoubtedly met Fr. DeSmet in that blizzard…:)
Not uncommon among secular anthropologists, unfortunately.
The Indians mentioned in the Jesuit Relations apparently converted because they could gain spirit power, because they were marginalized, every reason except the most obvious one, that they thought the Christian religion was true.
John G. Neihardt did not have a very good reputation in Nebraska. He was known to be rather, shall we say, condescending in his views. He refused to admit that Elk was a Christian.
Having a monument to Black Elk with a huge Crucifix was said to anger those who knew Neihardt. I think it was one of a long line of Nebraskan jokes at the expense of Neihardt.