Perhaps the most widely known and popularized figure to dress as a male in order to serve in the military is Hua Mulan. Mulan took her father’s place in the Chinese Army during the early middle ages disguised as a man so he would not have to serve in his old age. She served for 12 years before returning to her hometown and earned a significant amount of recognition and honors along the way. The heroic act was recorded in a poem as one of the first instances of undercover military service.

Deborah Sampson Massachusetts Historical Society
On the other side of the world and more than a thousand years later, Deborah Sampson fought in the American Revolutionary War. She enlisted in 1782, serving for nearly two years under the name of Robert Shurtleff. Sampson led expedition units and scouted territory, on the lookout for British troops in Manhattan. In 1783, a bullet hit Sampson in the thigh, leading to a near discovery of her identity. She removed the pistol ball herself to avoid being caught. Later that same year, however, Sampson became ill and her female identity was discovered when she collapsed in a Philadelphia hospital

Hannah Snell Bodleian Libraries
Some women served in their militaries for reasons other than patriotic duty or exploration. Hanna Snell married her husband and then gave birth to their child in 1746. A year later, after the death of their daughter, Snell’s husband abandoned her. She donned a male uniform and enlisted in the military to search for him. Before her unit returned to London, she was shot several times in the legs. Rather than visiting the surgeon on board the ship, Snell had a local woman remove the bullets. Once they had returned home, she revealed her real identity and spent several years singing on stages, performing military ditties.

Jane Dieulafoy Pierre Bonnefont, Nos grandes Françaises, Paris, Librairie Gedalge, 1905
Jane Dieulafoy also joined the ranks dressed as a male, but fought alongside her husband. He volunteered to fight in the Franco-Prussian War and Jane wanted to be right with him. She was a fierce advocate of women being able to join the military later during World War I.

Sarah Emma Edmonds, Geocities
Sarah Emma Edmonds, under the guise of Frank Thompson, joined the Union infantry during the Civil War. She served for a year as an aide to Colonel Poe and even went on intelligence missions spying on the Confederate Army. Edmonds had a prolific sense of duty and felt that she was called to serve for her country. Her five year military stint ended when she contracted malaria in 1865 and left the Army. In 1883, a memoir titled Nurse and Spy in the Union Army made her a public figure and she toured the country lecturing on her experiences.