In 1852, 26-year-old Matilda Joslyn Gage addressed the National Women’s Rights Convention in Syracuse, New York. Though a newly minted activist unaccustomed to public speaking, she came to the lectern with a clear message: History had been distorted, and it was essential to the cause of women’s rights to set it straight.

“So much is said against the unfitness of woman for public life,” Gage told to the crowd, before unraveling a trove of examples (Sappho, Queen Victoria) debunking the prejudice of the opposition. Gage felt a particular allegiance to women in the sciences, and directed attention to neglected academics and astronomers like Maria Cunitz, Elena Piscopia, and Anna Maria van Schurmann.

Gage is perhaps most famous for taking up the cause of women in the fields we now call STEM. Halfway through her career as a prominent suffragist, activist, and close associate of luminaries like Elizabeth Cady Stanton and Susan B. Anthony, Gage penned the 1870 essay, “Woman as an Inventor.” In it, she described case after case in which the contributions of women in the sciences had been forgotten or usurped by the nearest male — a phenomenon since dubbed the “Matilda effect,” in honor of her.

For Gage, the issue was personal. Raised in a family of progressive abolitionists (her house was a stop on the Underground Railroad), she held dear the values of personal liberty and free thought. But she found the world to be less accommodating. When she chose medicine as her vocation, she was roundly rejected by medical schools that only matriculated men. In medicine’s place, she chose activism.

Suffrage movement pioneers Susan B. Anthony and Elizabeth Cady Stanton. (Library of Congress)

“No assertion in reference to woman is more common than that she possesses no inventive or mechanical genius,” Gage wrote. She exposes this assumption to be a fairly recent misconception. Past cultures held aloft female intelligence as adept in the inventive arts, such as Leizu, an ancient Chinese empress of legend who invented the silk loom, and Athena, who presided over agriculture, tools, and musical instruments.

Moving away from myth and folklore, Gage drew from the panoply of real-life examples of female inventive and practical achievement. She cited 18th-century astronomer Maria Agnesi, paper-bag innovator Margaret E. Knight, sculptor and stone-treatment pioneer Harriet Hosmer, as well as Anna Ella Carroll, an adviser to Lincoln who engineered the successes of the Union’s campaign in Tennessee.

Gage emphasized the tendency for men, sometimes by simple proximity, to be given the credit for female genius. Such were the consequences of general prejudice, as well as a society that favored the husband in matters of patent ownership, or excluded women from the boardroom and the factory where their innovations might flourish.

In her most famous outlining of the phenomenon, Gage makes the claim that the cotton gin “owes its origin to a woman.” She explains that a Georgia woman named Catherine Littlefield Greene conceived of the cotton gin and put the responsibility of its construction on Eli Whitney. Historical records account amply for her involvement and sponsorship of Whitney, but for the claim that Greene saved the project by suggesting that the cotton gin replace its wooden teeth with metal bristles, Gage seems to be the only source.

Whatever ambiguity there is in the particulars, the overall message of Gage’s argument has been vindicated. In a 1993 journal article, science historian Margaret W. Rossiter gave the first description of the Matilda effect, inspired by Gage’s 1870 essay. “Calling attention to her and this age-old tendency,” wrote Rossiter, “may prod future scholars to include other such ‘Matildas’ and thus to write a better, more comprehensive, history and sociology of science.”

A cotton gin operated in Dahomey, Mississippi, 1890. Gage famously argued the machine—like many other technological innovations—”owes its origin to a woman.” (Library of Congress)

There was no shortage of examples. The 11th century provides the case of Trota of Salerno, female physician and writer of three medical texts named the Trotula, espousing expert advice on matters like pregnancy and skin care. But a few centuries later, a scholar rewrote her name to reflect the Latin masculine form, and shortly thereafter physicians and academics agreed a work of such importance must have come from a man, and chose as her replacement an imperial Roman physician who lived over a thousand years before.

History also provides many cases of what Rossiter calls “wife-collaborators.” In 1702, Maria Winckelmann Kirsch discovered a comet while her husband Gottfried was sleeping, but Gottfried put out the paper in his name (though he did correct the record eight years later). Of formal, institutional examples, geneticist Nettie Stevens was an early discoverer of XX and XY chromosomes, though her boss Edmund B. Wilson absorbed most of the credit. And Lise Meitner, who helped to discover nuclear fission, is the center of what Rossiter calls the “most notorious theft of Nobel credit.”

Some luminaries, like Rosalind Franklin and Ada Lovelace, have lately become more visible in response to long periods of neglect, while the success of movies like Hidden Figures shows how we are reconsidering our understanding of science and its history. As we continue to do so, there will no doubt be many more Matildas.