Čhetáŋ Sápa' (Black Hawk) (c. 1832 – c. 1890) was a medicine man and member of the Sans Arc or Itázipčho band of the Lakota people. He is most known for a series of 76 drawings that were later bound into a ledger book that depicts scenes of Lakota life and rituals. The ledger drawings were commissioned by William Edward Canton, a federal "Indian trader" at the Cheyenne River Indian Reservation. Black Hawk's drawings were drawn between 1880-1881. Today they are known as one of the most complete visual records of Lakota cosmology, ritual and daily life.