Mysterious Marks On Ancient Roman Glasswork Are Craftsmen ‘Logos’, Study Suggests

A quiet turn of an ancient glass vessel in a museum gallery has led to a sweeping reassessment of how Romes most intricate luxury glassware was made, and who made it.

Washington State University art historian and glassblower Hallie Meredith was examining a private collection of Roman glass cage cups at the Metropolitan Museum of Art in early 2023 when she noticed something long overlooked: abstract symbols carved on the reverse sides of the vessels. For centuries, scholars had dismissed these diamonds, leaves, and cross-like motifs as decorative fillers.

Merediths research now suggests they were something far more consequential — the makers marks of the artisans and workshops that carved these elaborate objects between 300 and 500 CE. Because she approaches ancient works through the lens of a practicing craftsperson, Meredith examined the cups from angles others had not.

“Because I am trained as a maker, I kept wanting to flip things over,” she said. “When that happens, patterns appear that everyone else has literally photographed out of the frame.”

That instinctive gesture soon revealed a network of repeating symbols across carved Roman vessels, linking them to shared workshop practices and a visual language spread among glassworkers from the fourth to sixth centuries CE.

Her findings, published in two recent papers in the Journal of Glass Studies and World Archaeology, build a case that Roman openwork vessels — known as diatretum cups — were produced not by solitary virtuosos but by coordinated teams of specialists working together over extended periods. Meredith traced tool marks, inscriptions, and unfinished fragments to show that engraving, polishing, and fine carving were distributed across craftworkers with distinct roles. The abstract openwork symbols, she argues, functioned like studio logos, identifying collective workshops rather than individual artists.

These cups, carved from a single block of glass into inner and outer layers connected by delicate bridges, have long been considered technical marvels. For more than two centuries, scholars have debated whether they were carved, cast, or blown. Few had examined the marks beyond the carved inscriptions wishing long life to their owners. Merediths work shifts the focus from technique to the people behind the craft, restoring visibility to the artisans whose labor shaped objects that have survived for 1,500 years.

Her forthcoming monograph, The Roman Craftworkers of Late Antiquity: A Social History of Glass Production and Related Industries, now in production with Cambridge University Press, expands this view by reconstructing the social worlds of these workers — the apprentices, engravers, polishers, and laborers whose contributions helped define late-antique luxury.

Merediths background as a glassblower gives the research a practical dimension. She understands what it takes to shape molten glass, and she brings that knowledge into the classroom at WSU, where students in her “Experiencing Ancient Making” course 3D print reconstructions, test ancient techniques, and examine artifacts with a virtual tool she created.

“The goal isnt perfect replication,” she said. “Its empathy. Ancient craftworkers can be understood differently when their production processes are experienced.”

Her next project pushes that effort further, merging art history with computer science. Working with WSU students, she is developing a database to catalogue non-standard writing across thousands of portable objects — including misspellings, mixed scripts, and coded inscriptions that earlier scholars dismissed as meaningless. She believes these may offer clues to multilingual workshops adapting to diverse audiences across the empire.

“Theres been a static picture of people who do the work,” Meredith said. “We presume we understand them because we focus on elites. But when the evidence is assembled, far more is known about these craftworkers than previously thought.”