In the years before the Civil War, the lives of American women were shaped by a set of ideals that historians call “the Cult of True Womanhood.” As men’s work moved away from the home and into shops, offices and factories, the household became a new kind of place: a private, feminized domestic sphere, a “haven in a heartless world.” “True women” devoted their lives to creating a clean, comfortable, nurturing home for their husbands and children.

During the Civil War, however, American women turned their attention to the world outside the home. Thousands of women in the North and South joined volunteer brigades and signed up to work as nurses. It was the first time in American history that women played a significant role in a war effort. By the end of the war, these experiences had expanded many Americans’ definitions of “true womanhood.”

With the outbreak of war in 1861, women and men alike eagerly volunteered to fight for the cause. In the Northern states, women organized ladies’ aid societies to supply the Union troops with everything they needed, from food (they baked and canned and planted fruit and vegetable gardens for the soldiers) to clothing (they sewed and laundered uniforms, knitted socks and gloves, mended blankets and embroidered quilts and pillowcases) to cash (they organized door-to-door fundraising campaigns, county fairs and performances of all kinds to raise money for medical supplies and other necessities).

But many women wanted to take a more active role in the war effort. Inspired by the work of Florence Nightingale and her fellow nurses in the Crimean War, they tried to find a way to work on the front lines, caring for sick and injured soldiers and keeping the rest of the Union troops healthy and safe.

In June 1861, they succeeded: The federal government agreed to create “a preventive hygienic and sanitary service for the benefit of the army” called the United States Sanitary Commission. The Sanitary Commission’s primary objective was to combat preventable diseases and infections by improving conditions (particularly “bad cookery” and bad hygiene) in army camps and hospitals. It also worked to provide relief to sick and wounded soldiers. By war’s end, the Sanitary Commission had provided almost $15 million in supplies—the vast majority of which had been collected by women—to the Union Army.

Nearly 20,000 women worked more directly for the Union war effort. Working-class white women and free and enslaved African American women worked as laundresses, cooks and “matrons,” and some 3,000 middle-class white women worked as nurses. The activist Dorothea Dix, the superintendent of Army nurses, put out a call for responsible, maternal volunteers who would not distract the troops or behave in unseemly or unfeminine ways: Dix insisted that her nurses be “past 30 years of age, healthy, plain almost to repulsion in dress and devoid of personal attractions.” (One of the most famous of these Union nurses was the writer Louisa May Alcott.)

Army nurses traveled from hospital to hospital, providing “humane and efficient care for wounded, sick and dying soldiers.” They also acted as mothers and housekeepers—“havens in a heartless world”—for the soldiers under their care.

White women in the South threw themselves into the war effort with the same zeal as their Northern counterparts. The Confederacy had less money and fewer resources than did the Union, however, so they did much of their work on their own or through local auxiliaries and relief societies. They, too, cooked and sewed for their boys. They provided uniforms, blankets, sandbags and other supplies for entire regiments. They wrote letters to soldiers and worked as untrained nurses in makeshift hospitals. They even cared for wounded soldiers in their homes.

Many Southern women, especially wealthy ones, relied on slaves for everything and had never had to do much work. However, even they were forced by the exigencies of wartime to expand their definitions of “proper” female behavior.

Enslaved women were, of course, not free to contribute to the Union cause. Moreover, they had never had the luxury of “true womanhood” to begin with.

The Civil War promised freedom, but it also added to these women’s burdens. In addition to their own plantation and household labor, many enslaved women had to do the work of their husbands and partners too: The Confederate Army frequently recruited enslaved men, and slaveowners fleeing from Union troops often took their valuable male enslaved workers, but not women and children, with them. (Working-class white women had a similar experience: While their husbands, fathers and brothers fought in the Army, they were left to provide for their families on their own.)

During the Civil War, women especially faced a host of new duties and responsibilities. For the most part, these new roles applied the ideals of Victorian domesticity to “useful and patriotic ends.” However, these wartime contributions did help expand many women’s ideas about what their “proper place” should be.