This exhibit celebrates the important role that cryptology played during the American Civil War. During America's first century, secret writing — cryptography — figured in many instances in which lives and fortunes were at stake and confidentiality was desired. Until nearly the middle of the 19th century, large armies moved over an extensive battlefield unassisted by any special technology to aid long distance communications or even tactical communications. In 1844, Samuel F. B. Morse successfully tested his improved electromagnetic telegraph between Washington and Baltimore. At the time of the American Civil War, both sides began encrypting high-level messages to be transmitted on the telegraph. Both sides established cipher bureaus in their respective capitals to work on enemy encrypted messages, one of the early examples of a centralized intelligence activity in the United States.