The Assimilation of Sioux Students at Carlisle Indian School This pair of before and after photographs of Wounded Yellow Robe, Timber Yellow Robe, and Henry Standing Bear reveals the distinct turn away from tribal culture upon enrolling in Carlisle Indian School in 1883. The forced assimilation policy at such schools set out to divest the Indians of any remnant of their former lives. Archives and Special Collections, Dickinson College.