Mermaidcore is back. It never really went away.

The half-fish, half-woman sea creatures took hold in popular culture in the early 20th century and helped liberate women and girls from swimming costumes fit for drowning.

Since antiquity, mermaids have embodied our fantasies of the briny deep.unorobus/adobe

Shell-adorned bikini tops. Fishtail skirts. Starfish accessories. Seafoam green eyeshadow. “Mermaidcore” — the personification of aquatic glamour and physical beauty — is back, thanks to Disney’s latest live-action blockbuster, “The Little Mermaid.”

Since antiquity, mermaids have embodied our fantasies of the briny deep. Inscrutable, various, and generally scantily clad, these half-fish, half-woman mythological creatures are shapeshifting figures known the world over, from the sirens of the Aegean, to the jiaoxiao, or merfolk, of the South China Sea, to Africa’s Mami Wata, whose origin is often traced to the coast of Guinea.

As the industrial revolution’s rising tide traded wonder for rationality, “real” reports from the ocean began to abate. But rather than disappear into myth, mermaids performed their next act of transformation: moving from the water to the stage and silent screen. The early 1900s productions that resulted popularized less cumbersome swim fashions — the original mermaidcore — that permitted girls and women greater freedom in style and sport.

Of all the early mermaid tales, it was “Neptune’s Daughter” that most captured the public imagination. Staged in the Hippodrome, the famed New York theater that boasted a stage 12 times larger than its Broadway counterparts, the show was an instant hit when it debuted in late 1906. Audiences flocked to see the actresses playing mermaids dive into an 8,000-gallon clear tank filled with water.

“Neptune’s Daughter” created the illusion of mermaids breathing underwater. To maintain the fantasy, rehearsals were conducted with utmost secrecy, with management threatening to fire anyone who gave away the gimmick (submarine chambers) that allowed the actresses to linger below the surface. Such precautions paid off. “No spectacular invention or innovation of recent years has aroused such popular interest or awakened such widespread curiosity as the mermaid scene,” observed a reviewer in The New York Times.

A silent film production of “Neptune’s Daughter” followed in 1914, starring champion swimmer and actress Annette “the Australian Mermaid” Kellerman.

Swimming, long considered a masculine domain, had opened up to women relatively early in Kellerman’s home nation. Around the 1830s, middle-class women swam recreationally in Australia, and by the time Kellerman entered the pool at 9 years old, a burgeoning competitive scene was underway. Because Kellerman was bowlegged, her parents had put her in swimming lessons as a form of physical therapy. Though she was weak on land, she found she was athletic and graceful in the water. She began winning swimming and diving competitions against girls and boys. By the time she made her way to the United States in 1906, she had already attempted to swim across the English Channel and was well on her way to achieving international fame.

A poster for the 1914 film "Neptune's Daughter," starring Australian swimming sensation Annette Kellerman.Wikimedia Commons

But when Kellerman arrived in America, she found that women’s swimming culture was stuck in Victorian times. Because there was no long-distance swimming to be had, she first made money doing water stunts in vaudeville performances. She also began campaigning to change American swimwear. As she reasoned, if women wanted to enter the pool, they first needed the freedom to abandon the cumbersome bathing costume of wool skirt, blouse, stockings, and swim shoes that was literally weighing them down.

“The best costume is the cheap, ordinary stockinette suit, which clings close to the figure, and the closer the better. It should be sleeveless and there should be no skirts. Skirts carry water and retard the swimmer. They are very pretty and appropriate for the seaside, but not for the swimming pool. Stockings may be worn if they fit tightly, but under no circumstances should shoes be used.”

That excerpt comes from the 1907 article “Swimming Hints,” one of many Kellerman authored to encourage more women and girls to lose their bulky swim costumes and adopt a modern one-piece swimsuit.

But perhaps nothing did more to change the conversation than her mermaid motion pictures.

Kellerman made her US film debut in 1911, starring in two Vitagraph shorts, “The Mermaid” and “Siren of the Sea.” The silent fantasy genre helped Kellerman transcend the norms of the day, turning her formfitting one-pieces into swimmable mermaid costumes. This layer of pretend helped neutralize “any suggestion of indecency” that the star’s otherwise head-turning outfits might have engendered, as author Christine Schmidt wrote in her 2013 book “The Swimsuit: Fashion From Poolside to Catwalk.” The public watched with fascination. Kellerman was heralded by the press at the time as being “the most perfectly formed woman in the world.” And an audience hungry to be just like her followed her every move, eager to copy everything about her, including, in time, the trademark “Annette Kellerman suit.”

By the time Kellerman’s film career wound down a decade later, most women were starting to wear the same one-piece swimsuits the star first championed at the turn of the century.

While mermaidcore wasn’t alone in opening up the waters to women, it undeniably lent its sparkle to the cause, offering glamour that helped them transform their reality on land and sea.

Jackie Mansky is senior editor at Zócalo Public Square, where a version of this essay originally appeared.