"Buffalo Soldiers", because of the texture of their hair. Pratt's long and active military career included eight years in the Great Plains, during the Indian Wars. He participated in the Washita campaign of 1868–1869 and the Red River War of 1874–1875. The severe winter of 1874-1875 resulted in many hostiles surrendering to US Indian Agents for their tribes. Pratt was responsible for gathering testimony to assess charges against men for actions outside warfare. He worked with interpreters and prisoners to clear as many charges as possible. Pratt was promoted to captain in February 1883; major in July 1898; lieutenant colonel in February 1901; and to colonel in January 1903. He retired from the Army in February 1903; in April 1904 he was advanced to brigadier general on the Retired List. Fort Marion and Carlisle After the Indian wars subsided, President Grant's Attorney General concluded that a state of war could not exist between a nation and its wards (which the federally recognized tribes were considered). He ordered the prisoners to be sent as prisoners of war for permanent imprisonment at Fort Marion, St. Augustine, Florida. Pratt was chosen to lead and supervise the prisoners at the fort, because he had experience with both the Indians and interpreters from working on their cases. After he requested further authority over the prisoners, he began to experiment with education at the fort. In the 1870s at Fort Marion, he introduced classes in the English language, art, and craftsmanship to several dozen prisoners who had been chosen from among those who had surrendered in the Indian Territory at the end of the Red River War. In addition, he worked to give prisoners agency and some independence: enlisting them in guard duty, assigning them other supervisory roles over their community, leading marching and maneuvers for exercise. On November 1, 1879, he founded the Carlisle Indian Industrial School at Carlisle, Pennsylvania, the first of many off-reservation boarding schools for Native Americans. Pratt did not regard his innovations at Fort Marion as limited to Native Americans. He developed the paradigm of compulsory immersion education. At various times, it would be used in attempted assimilation of other minorities in the United States and its territories, including African Americans, Puerto Ricans, Mexicans, Latinos, Pacific Islanders, Asians, and Mormons. He took his pedagogical inspiration from the Puritans. Cultural assimilation of Native Americans Pratt instituted a practice of Americanization of Native