The letter from C.W. Foster of the U.S. War Department to Douglass requesting his help in the recruiting effort, August 13, 1863
CREDIT: Foster, C. W. "C. W. Foster, U.S. War Department, to Frederick Douglass, August 13, 1863.(letter)." 1863. African American Odyssey: The Civil War, Soldiers and Missionaries, Library of Congress.