As the United States grew in the early 1800s, pressure increased on American Indian groups to move west.  After the Louisiana Purchase in 1803, some eastern tribes took the government’s offer to move west of the Mississippi River.  Of course, much of this land was already occupied by peoples such as the Osages, Wichita, and Caddos as well as the Comanche and Kiowas farther west.  This pressure grew more intense in the 1820s and 1830s as members of the southeastern tribes (known as the “civilized” tribes or Five Tribes: Cherokee, Creek, Choctaw, Chickasaw, and Seminole) found ways to assimilate to the culture and government of the United States but would not move from their lands.  The United States decided that the best course of action was to remove these groups to a defined area west of the Mississippi and created what was known as Indian Territory.

Some groups from the Old Northwest, like the Foxes, Sacs, and Potawatomie moved to Indian Territory early on, leaving their homeland that was torn apart by conflict.  The Southeastern tribes resisted removal and the United States’ response was the Indian Removal Act in 1830.  Over the next decade the United States aggressively forced people of the Five Tribes to move to Indian Territory.  This created a traumatic diaspora for the people forced from their homes, as well as for the people already living in Indian Territory. During the Civil War the leadership of the Five Tribes supported the Confederacy and as a result lost power from previous treaties after defeat in 1865.  The war significantly weakened the larger tribes’ negotiating rights in upcoming conflicts over land.  The size of the Indian Territory was reduced and parts of the land that had belonged to the Five Tribes were given to tribes that were moved from Kansas such as Sac and Fox.

It was into this world that Prettyman entered with his camera and equipment in 1883.  Largely travelling alone, he showed himself to be quite resourceful, eating what he was able to hunt and using his connections from his home in Arkansas City, Kansas to befriend many American Indian tribes.  Throughout the next ten years Prettyman engineered extended stays with most of the tribes in Indian Territory, leaving behind a rich photographic history of cultures that were in the midst of major change.  Prettyman was not the only White American interested in the Indian Territory at this time, ranchers were using the territory as a major thoroughfare and Boomers were pressuring the government to open the land for settlement.  These forces were growing extremely powerful and in just a few short years would vastly alter the landscape of Indian Territory; Prettyman captured these events as well.