Beloved in Civil War lore as the "Angel of the Battlefield," Clarissa "Clara" Harlowe Barton (1821–1912) was the youngest of five children born to Stephen and Sarah Barton of North Oxford, Massachusetts. Following years of service as a teacher, Clara returned to Washington, D.C., in 1860 to resume work as a clerk in the federal Patent Office. With the outbreak of the Civil War, she immediately recognized a need for medical assistance at the front lines of the conflict. Despite having little prior training as a nurse, and with no expectation that her services would be remunerated, Clara Barton heroically risked her life to provide succor to the wounded and dying soldiers on several battlefields, including Antietam, Fredericksburg, and Cold Harbor. Late in the war, President Lincoln authorized Barton to form the "Office of Correspondence with Friends of Missing Men of the United States Army." She established the Missing Soldier Office in Washington, D.C., which exchanged 63,000 letters between 1865 and 1868; an effort that eventually identified more than 22,000 missing Union soldiers. Her efforts also led to the establishment of the national cemetery at Andersonville Prison in Georgia, where the graves of 13,000 men were identified. The crowning achievement of Barton's career occurred after the war, when she founded the American Red Cross in 1881.