The Civil War gave Clara Barton her famous nickname

After her brother David fell off a barn roof in 1833, Barton devoted herself to taking care of him for the next two years as he recovered. Even though nursing was once regarded as a male-dominated profession, Clara's early nursing experience found a place to flourish during the Civil War, and at the age of 39, she discovered her calling.

Barton found injured members of the 6th Massachusetts Infantry residing in the Senate chamber of the U.S. Capitol one week after hostilities began. She cared for them with supplies from her house and eventually started her own supply distribution company. She was given the nickname "Angel of the Battlefield" for her humanitarian efforts. She is initially known to have provided assistance during the Battle of Cedar Mountain in Culpeper County, Virginia, in 1862. In the two-day battle, more than 3000 Union and Confederate men were either killed or injured.