The unlikely band of American women who crossed the Atlantic into war-torn France in February 1918 included six doctors, 13 nurses, a dentist, a plumber, an electrician, a carpenter and a mechanic. They were the first wave of women determined to build hospitals to treat the war-wounded and help the Allied effort in World War I. But they had an ulterior motive as well: to prove beyond doubt that women were just as brave, competent and self-sacrificing as men—and thus deserved the right to vote back home.

They did so working shoulder to shoulder alongside men in makeshift hospitals, operating under enemy fire, treating soldiers and war refugees who had been maimed, wounded, gassed or ravaged by influenza.

World War I offered many new opportunities for women—and suffragist groups pushed for even more. At the time, only about six percent of American doctors were female and most could only find positions in hospitals established by and for women. Soon after America entered the war in 1917, four New York-based physicians, Drs. Caroline Finley, Alice Gregory, Mary Lee Edward and Anna Von Sholly, offered their medical services to the U.S. military and were firmly rebuffed because they were women.

But the desperate French welcomed the women—along with whatever funding and supplies they could bring—into the Service de Santé, which oversaw French military medical care.

The National American Woman Suffrage Association (NAWSA), with some 2 million members nationwide, joined forces with the women doctors. At its December 1917 meeting, NAWSA pledged $175,000 to sponsor an all-female team of physicians, nurses and support personnel to build and staff hospitals in France. They called it the Women's Oversea Hospitals Unit, deliberately leaving "suffrage" out of the title—"for fear it would queer it," according to accounts at the time.

In all, 78 women doctors and their assistants risked their lives under NAWSA's suffragist banner in World War I, but their stories remain largely lost to history. "Practically no information exists about the women doctors and the Women's Oversea Hospitals Unit, outside of the rare mention in an obituary or the self-published pamphlet authored by a NAWSA volunteer," writes Kate Clarke Lemay, a historian at the National Portrait Gallery who chronicled what she could find in her 2019 book, Votes for Women! A Portrait of Persistence.

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The Women's Oversea Hospitals' first unit intended to build a hospital in Guiscard, in northern France, but the Germans had overrun it by the time the women arrived. Twelve of them dispatched instead to Château Ognon, a 17th-century estate-turned-military evacuation hospital outside of Paris.

The French military surgeons who greeted their truck roared with laughter when they saw that their reinforcements were American women.

But the laughter didn't last long. In the first 36 hours, the women treated some 650 cases. "Wounded men started coming in so fast there was no time to think of men people or women people, just human needs," Dr. Olga Povitsky wrote in a 1918 letter excerpted by the Woman Citizen, NAWSA's weekly newspaper. Soon the Americans were in charge of entire wards and operating alongside French surgeons.

Château Ognon, situated along the route German bombers took to attack Paris, was itself bombed in the Germans’ final offensive of the war. Dozens of patients, staffers and soldiers were killed or wounded as the Germans lobbed 3,000 pieces of artillery on the hospital between May 27 and June 16. But the women doctors never flinched. "Bombs shook the operating room theater and the barracks. Cannons roared and planes vibrated the atmosphere," wrote Dr. Edward, who operated on more than 100 casualties in a 24-hour period under enemy fire.

For their bravery, the French government later awarded the Croix de Guerre to Drs. Finley, Edward and Von Sholly and nurse Jane McKee.

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Other members of the first suffragist unit were sent build a 50-bed hospital at Labouheyre, in southwestern France, to care for refugees fleeing the German offensive. German POWs framed the barracks, supervised by carpenter Florence Kober, who spoke German. But the women built everything else, from furnishing the hospital with running water and electricity to outfitting it with closets and shelves.

"We had to do all our own heavy work, including making coffins," Dr. Mabel Seagrave, an ear, nose and throat specialist from Seattle, later told a reporter. "Our plumber was a former New York actress. Our carpenter was just out of a fashionable girl’s school. Our chauffeurs were all girls.”

Directed by Dr. Seagrave and Dr. Marie Formad, a surgeon from Newark, N.J., the hospital soon grew to 125 beds and treated more than 10,000 refugees during its existence. The Women's Apparel Association, representing the U.S. fashion industry from factory workers to department-store buyers, provided more than $100,000 for its funding.

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In the summer of 1918, the French asked NAWSA to send 50 more women doctors, nurses and assistants to set up a 300-bed hospital in Nancy for victims of gas attacks, along with a mobile unit that could travel to the frontlines. NAWSA leaders scoured the country for female physicians with appropriate experience, but warned candidates, "This service may be dangerous and will require women of good nerve."

Among those who volunteered were Dr. Marie Lefort, a specialist in skin diseases from Bellevue Hospital Dispensary in New York; Dr. Nellie Barsness, an ophthalmologist from St. Paul, Minnesota and Anna McNamara, a mechanic needed to drive the mobile unit's three-ton truck and run the steam engine needed to heat water for baths and disinfecting clothes. Several of the women suffered gas attacks themselves, including Dr. Irene Morse, a lung specialist from Clinton, Connecticut, who died of the after-effects in 1933.

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The signing of the armistice in November 1918 didn't end the need for medical care as thousands of repatriates, many of them sick, wounded and starving, traversed the ravaged French countryside. Members of the Women's Oversea Hospitals units stayed on for months in different roles. Dr. Finley's group was deployed to Cambrai, on the German-French border, where 1,500 refugees were returning every day. When she reported to the commanding officer there, he said, "Thank God you've come," Dr. Finley wrote.

Other American women transformed a bombed-out girl's boarding school in Nancy into the Jeanne d'Arc Hospital, where they treated thousands more refugees. "These poor people come in on trains that have sometimes taken days," wrote Dr. Lefort. "They have the hunted expressions one sometimes sees in animals."

Several other women's groups also sent female physicians to Europe in World War I, including the Medical Women's National Association, Smith College and philanthropist Anna Morgan, the daughter of J. P. Morgan.

In all, some 25,000 American women journeyed to France during World War I to support the Allied efforts. More than 100 were decorated by foreign governments, but not one was ever recognized by the U.S. government for her service.

It's unclear how much their hard work and sacrifice helped the American suffragist cause.

After many failed attempts, Congress finally passed the 19th amendment, which guaranteed women the right to vote, in 1919. It was ratified by the necessary 36 states in 1920.

But aside from brief newspaper accounts, the contributions of the female physicians went largely unrecognized. "These women went through hell just to get the opportunity to serve," says Lemay, "and they became mostly footnotes in history books."