At the conclusion of the Southern Plains Indian war, a group of 72 warriors, primarily Kiowas, Cheyennes, and Arapahoes, were taken prisoner and transported to Fort Marion, in St. Augustine, Florida, where they were held as hostages to ensure the peaceful conduct of their tribes. The officer in charge of the prisoners, Lt. Richard Pratt, saw their captivity as an opportunity to demonstrate the value of Indian education, and the men were offered English lessons as well as Christian religious instruction. He also encouraged the men to produce souvenirs for sale to the tourists who frequented St. Augustine, and 23 of the Fort Marion prisoners are known to have produced drawings during their tenure in the East, often in small drawing books. They were able to keep the money from their sales, and many sent funds home to help support their families.

http://www.nmnh.si.edu/naa/kiowa/kiowa.htm