Photo of Sitting Bull wearing a crucifix
"Have you ever seen the non-cropped version of the Sitting Bull?" was the question put to Taylor Marshall by Fr Phil Wolfe. The above photo (from Taylor's Canterbury Tales blog) may seem very familiar, but the crucifix is not normally shown.
Sitting Bull became a Catholic in later life, being influenced by the friendship of the French Canadians. Roman Christendom also has a lengthy post about him: A Roman Catholic Sioux leader: Chief Sitting Bull