When we think of women’s roles during the Civil War, we imagine them as nurses, cooks, washerwomen, or spies. In fact, at least 400 women fought alongside men, but researchers believe that number may be greatly underestimated. These women ignored the social conventions and bravely fought for their beliefs, putting their lives and reputations at risk.

Take, for example, Lizzie Hoffman, a black woman from Winchester, Virginia, who joined the 45th U.S. Colored Infantry disguised as a man. She fought for two years, until her gender was discovered as she boarded a steamer with her fellow soldiers, a regiment composed of both freedmen and escaped slaves. She was arrested and charged at the Central Guard House in Washington, D.C. for masquerading as a man, then forced to put on a dress.

The military prohibited the recruitment of women for combat, so they took it upon themselves to get in by any means necessary. Women joined for many reasons, including the need to be with their husbands or other relatives or simply to heroically join the war effort.

It wasn’t so unheard of that a woman would gender-bend during this time. According to the book They Fought Like Demons: Women Soldiers in the American Civil War, by historians DeAnne Blanton and Lauren Cook Wike, “Cross-dressing female heroines, both fictional and real, were a standard commodity in popular culture. In fact, military and sailor women were celebrated in popular novels, ballads and poetry, from the seventeenth century through the Victorian age.”

Most of the women creating new identities and marching off to war were white. However, researchers speculate that there were also a good number of African American women who fought in the Civil War and they were underreported. Like their male counterparts, they were motivated by a great cause: the liberation of their people. Whatever the risks — being outed as a woman, battlefield injuries, even death — it was all worth it.

Maria Lewis was only 17 years old when she escaped slavery to join the Union Army. She was part of the 8th New York Cavalry, a white unit that fought in the Battle of Waynesboro — so she was apparently fair-skinned enough to also pass as white. This cavalry succeeded in destroying the Confederate Army in the Shenandoah Valley. Lewis, using the alias George Harris, was among a group of soldiers who later presented the 17 flags and 500 prisoners they captured to Secretary of War Edwin Stanton in Washington, D.C. She chose her alias from a character from Uncle Tom’s Cabin, a black man who disguised himself as a Spaniard to escape slavery.

The only details about her life are contained in the diary entries of Julia Wilbur, a Rochester, New York, abolitionist whom Maria met at the end of the war. Wilbur described her as “very muscular and strong,” and someone who was constantly on the saddle during the Battle of Waynesboro, in March 1865.

Historians speculate that Wilbur’s brother, Lewis V. Griffin, a second lieutenant in the 8th Cavalry and an abolitionist, protected her secret, which was why Lewis felt comfortable reaching out to Wilbur after the war.

On April 4, 1865, Wilbur wrote the following in her diary:

A colored woman has been here who has been with the 8th N.Y. Cav. for the last 18 months. She knows Mr. Griffin. She wore a uniform, rode a horse and carried a sword and carbine just like a man. The officers protected her and she was with them mostly. The regiment didn’t know that she was a woman. She was called Geo. Harris, but her real name is Maria Lewis. She is from Albermarle Co. Va. and escaped to the Union army.

Lewis alternated between her true identity and her alter ego. She was known to meet with Wilbur in full army regalia and also walk the streets in a dress. She initially saw joining the military as a way to gain freedom and intended to leave as soon as she could, but she found army life exciting. Still, she’d eventually return to her life as a woman.

“Maria Lewis has doffed her uniform and wishes to return to womanly ways and occupations,” Wilbur wrote. “I gave her a chemise, petticoat and hoops, and we shall see that she has a good place to work.”

Like Lizzie Hoffman, Maria Lewis continues to puzzle historians. And like other black soldiers of that time and beyond, their contributions to the war effort and the liberation of black people are largely unsung.