Pierre-Jean De Smet (30 January 1801 – 23 May 1873), also known as Pieter-Jan De Smet, was a Belgian Catholic priest and member of the Society of Jesus (Jesuits).
He is known for his widespread missionary work in the mid-19th century among the Native American peoples, in the midwestern and northwestern United States and western Canada.
His extensive travels as a missionary were said to total 180,000 miles (290,000 km).
He was known as the "Friend of Sitting Bull", because he persuaded the Sioux war chief to participate in negotiations with the United States government for the 1868 Treaty of Fort Laramie.
Source: Library of Congress Prints and Photographs Division. Brady-Handy Photograph Collection. http://hdl.loc.gov/loc.pnp/cwpbh.03561. CALL NUMBER: LC-BH824- 5343 <P&P>[P&P] License: CC-PD-Mark