Ancient Roman glass reveals a hidden “language”

LLong-overlooked clues hidden in ancient Roman glassware may have revealed a secret collective of artisans. This is all thanks to archaeologist and glassblower Hallie Meredith, who once gazed upon Roman objects called glass cage cups or diareta at the Metropolitan Museum of Art in New York. She turned one over, sparking a series of discoveries.

“Because I have a background as a designer, I’ve always wanted to turn things around,” Meredith said in a statement. “When this happens, patterns appear that literally everyone has photographed out of the frame.”

Meredith noticed designs including crosses, leaves and diamonds next to an inscription “wishing [the cup’s] owner a long life. Such symbols were previously characterized as decorative, but she saw something more. This chance observation turned into a glass treasure hunt: she found similar symbols on other diareta dated between the 4th and 6th centuries, works that have intrigued researchers for centuries.

Read more: »The strange life of glass»

It was already known that artisans started with large pieces of thick glass, which they cut into two layers connected by intricate glass bridges. Meredith’s detective work suggests that these glassmakers were using the symbols found on these cups to form a visual language, according to findings reported in an April report. Journal of Glass Studies paper and a World Archeology article published last month.

“It is clear that such symbols were not merely ‘decorative,’ but rather were meaningful and intentional in ways that were not previously recognized or appreciated,” she wrote in the Journal of Glass Studies paper.

After inspecting unfinished fragments of diaretatool marks and inscriptions, Meredith suggests that collectives of apprentices, polishers, and engravers collaborated on these magnificent pieces, painstaking projects that could take years to complete. These motifs perhaps referred to the regional workshops where the cups were made. “They were the ancient equivalent of a brand,” she said.

Meredith hopes her work can spark new discoveries about diareta production – and paint a more complex picture of ancient artisans. “There’s a static picture of the people doing the work,” Meredith said. “We assume we understand them because we focus on the elites. But once the evidence is gathered, much more is known about these artisans than previously thought.”

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Main image: Carole Raddato / Wikimedia Commons

• Molly Glick

  Published on November 14, 2025

  Molly Glick is the newsletter editor of Nautilus.