Before artistic swimming debuted as an Olympic discipline at the 1984 Games in Los Angeles, it was commonly associated not with the Olympics, but with the golden age of Hollywood. And, even earlier, artistic swimming performances entertained ancient Romans in the first century, A.D.

In 1944, MGM released Bathing Beauty, a Technicolor movie musical created especially for its star, Esther Williams. As a former national champion swimmer, Williams’ dreams of winning Olympic gold were dashed when the 1940 Olympics were canceled due to the outbreak of World War II.

Over the next decade she would become one of Hollywood’s most bankable stars, thanks to a series of “aquamusicals” featuring elaborately costumed, staged and choreographed displays of what was then known as synchronized swimming and diving.

But the roots of artistic swimming stretch back all the way to ancient Rome. Alongside the well-chronicled gladiatorial battles, Roman emperors also staged massive aquatic spectacles in man-made lakes and flooded amphitheaters in front of roaring crowds.

Many of these displays were reenactments of historic naval battles, known as naumachiae, including one designed to celebrate Julius Caesar’s military achievements in 46 B.C. However, according to a written account by the first-century A.D. poet Martial, at least one aquatic spectacle featured a group of female swimmers portraying Nereids, the sea nymphs of Greek mythology.

“Martial was a society poet—he cultivated patrons, of whom the most important was the emperor,” says Kathleen Coleman, the James Loeb Professor of the Classics at Harvard University. “His major output is from the reign of Domitian, who reigned from 81 to 96, and he published what have survived as 15 separate books of epigrams, of which the first may have been composed under Domitian’s predecessor, Titus. It survived in a very mutilated condition in a few manuscripts, but it contains the only actual evidence for what we might want to call synchronized swimming in the Roman world.”

In Epigram 30 of his Liber Spectaculorum, Martial writes of a nighttime display put on during Titus’ reign, during which a “well-trained group of Nereids were frolicking all over the water and describing richly varied patterns on the compliant waves.” His account goes on to describe seeing the shape of a trident, an anchor and “broad sails billowing in distinctive folds.” Coleman believes this refers to the Nereids’ performance of a type of aquatic ballet or miming of these formations on the surface of the water.

Though it’s unclear exactly where this particular aquatic spectacle would have taken place, one likely location is the Colosseum, the giant amphitheater first constructed between A.D. 70–72 under Titus and Domitian’s father, Vespasian. If so, Coleman says the arena likely would have been flooded with water pumped from sources in the mountains near Rome via aqueducts.

Another possible location is the man-made lake created by an earlier Roman emperor, Augustus, on the other side of the Tiber River near Trastavere, where earlier stagings of naval battles were known to have been held.

As the Nereids were sea nymphs, daughters of the sea god Nereus, the performers in this aquatic spectacle were most likely female, Coleman says. They also likely performed naked; as this would have been taboo in Roman culture, the performers may have been women of lower social stature, possibly even enslaved.

“It would seem completely contrary to the myth if they were clothed,” Coleman explains. “They may have been slaves, or maybe they rounded up freeborn prostitutes. There’s no evidence whatsoever [for who they might have been].”

Just as many of the naumachiae portrayed great sea battles from the ancient past, the performance by the Nereids likely served to link ancient Romans—and especially their emperors—to the myths that were so vital to their society and culture. Among the most famous Nereids were Amphitrite (wife of the sea god Poseidon and mother of Triton) and Thetis (mother of the hero Achilles), whom Martial specifically mentions in his account of the aquatic display.

“We put a very sharp line between myth and history, but we are in a sort of post-scientific age, whereas in antiquity, so much was inexplicable,” Coleman says. “The reenactments of these myths are a way of enlivening the myths, of bringing them right into your vision.”