Born in Massachusetts in 1821, Clara Barton had struggled with issues of insecurity throughout life, but the beginning of the Civil War provided her with a new spirit and mission. She was often frustrated by army officials, who seemed not to comprehend the importance of providing medical supplies, but the Battle of Antietam was her breakthrough moment. As she later described, Barton followed the Army of the Potomac with three supply wagons, and she arrived at the battlefield early on the morning of September 17, 1862.

Never had the need been so obvious or immediate. Wounded men were brought into the army tent literally by the minute. Barton and a few assistants were there to assist in the terrible choices that army surgeons had to make. Probably two times out of three, the wounded soldier had to lose a limb in order to save his life. As the day wore on, Barton experienced war in all its terror. One wounded soldier was killed by a cannon shot, and the blood spurted all over her. She continued her work. The irony in all of this is that Barton—to the end of her days—never regarded nursing as her number-one priority. In a career that spanned the Civil War and the Spanish-American War, she always considered herself primarily as a deliverer of much-needed medical supplies.