When did Clara Barton get called to war?

In August of 1862 she got permission from Quartermaster Daniel Rucker, to work on the front lines of the American Civil War. She distributed stores, cleaned field hospitals, applied dressings and served food to wounded soldiers at such battles as Cedar Mountain, Second Bull Run, Antietam and Fredericksburg. In 1864, she was appointed the "lady in charge" of all the hospitals of the Army of the James and by wars end she would become known as the "Angle of the Battlefield." In 1870 she would assist the Grand Duchess of Baden prepare military hospitals during the Franco-Prussian War, by wars end she would be decorated with both the Golden Cross of Baden and the Prussian Iron Cross. Her last war would be the Spanish-American War (1898) where she worked in hospitals in Cuba at the age of 77.