Flora Sandes was born on in Nether Poppleton, Yorkshire, the youngest daughter of a large Anglo-Irish family. Her father was a clergyman and the family moved several times during her childhood. She was educated by governesses and grew up a tomboy who liked riding, shooting, and driving a car. After training as a stenographer in London, she worked as a secretary in Cairo, camped in British Columbia, Canada, and worked her way across the USA. In 1910, she joined Mabel Annie St. Clair Stobart in forming the Women's Sick and Wounded Convoy, which went into service in Serbia and Bulgaria in 1912 during the First Balkan War. At the start of World War I in 1914, Flora volunteered for a St. John Ambulance unit destined for Serbia on the Eastern Front. There she joined the Serbian Red Cross and drove an ambulance for the Serbian Army. She then enlisted as a soldier, the only British woman to serve as a soldier in combat in WWI. In 1916, she was seriously wounded during hand-to-hand fighting and was promoted to sergeant-major and decorated with Serbia's highest honor, the King George Star. That same year, she published her autobiography, An English Woman-Sergeant in the Serbian Army, based on her letters and diaries. She spent the remainder of the war running a hospital. At the end of the war, she became the first woman commissioned as an officer. In 1927, she married Yuri Yudenitch, a fellow officer and former White Army general 12 years her junior. The couple lived for a while in France, but later returned to Serbia, which had become part of Yugoslavia, settling in Belgrade. She went on a world tour to lecture on her wartime experiences. She and her husband were recalled to military service at the outbreak of World War II, but were forestalled by the German invasion of Yugoslavia. They were briefly interned by the Germans before being released. Yudenitch died in 1941 and Flora subsequently returned to England.