Tiny symbols engraved into ancient Roman drinkware may be more than merely decorative accents. After two years of research, an art historian believes that the designs on glass Roman cage cups are testaments to the skill and collaborative efforts required to craft some of the empire’s most renowned pieces of glasswork.
The talent of ancient Rome’s artisans is displayed across the empire’s vast archaeological remains, such as its architecture, mosaics, and sculptures. However, the mysterious diatretum (or the plural, diatreta) has particularly fascinated experts for over 250 years. Also known as a cage cup or reticulated cup, these vessels rose to popularity during the 4th century CE, and are considered apex examples of Roman glassworking. Each diatretum began as a single block of thick glass. Trained sculptors then carved the material into two delicately linked concentric layers–an inner beaker housed inside a geometric framework. Although the latticework is incredibly light, the luxury items are sturdy enough that a handful remain largely intact when uncovered today.
Another curious aspect to diatreta are the abstract symbols often carved above an inscription. For example, one cage cup at the Metropolitan Museum of Art in New York City features crosses, diamonds, and leaves next to a dedication in Latin wishing the owner a long life. For years, most researchers believed the shapes were simply additional artistic flourishes. But after examining the piece firsthand in 2023, Washington State University art expert Hallie Meredith set out to compare it with other examples of Roman cage cups. Now, Meredith believes the details are far more personal. In addition to her findings published in two recent studies, she also cites her years of experience as a glassworker as helping her make this connection.
“Because I am trained as a maker, I kept wanting to flip things over,” she said in a university statement. “When that happens, patterns appear that everyone else has literally photographed out of the frame.”
Meredith catalogued and traced the symbols found on the original diatretum example to similar vessels in other museum collections. She was then able to match them to a visual language system used by glassmakers in Rome between the 4th and 6th centuries CE. Additional analysis of tool markings as well as unfinished pieces and inscriptions revealed each cage cup wasn’t made by a single artisan. Instead, they required entire teams of polishers, engravers, and their apprentices.
“They weren’t personal autographs,” said Meredith. “They were the ancient equivalent of a brand.”
She added that with a better understanding of the culture surrounding each work of art, historians and everyday admirers can gain more of an appreciation for projects that sometimes took months or even years to accomplish.
“There’s been a static picture of people who do the work,” Meredith said. “We presume we understand them because we focus on [the] elites. But when the evidence is assembled, far more is known about these craftworkers than previously thought.”
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