Technician cracks 1,600-year-old mystery to replicate Roman masterpiece
The remarkable colour-changing effect observed in a famous Roman masterpiece has been successfully reproduced in quantity for the first time in 1,600 years by a University of Sheffield technician.
For the first time, University of Sheffield experts in the School of Chemical, Materials and Biological Engineering have successfully reproduced the ‘dichroic’ glass used to make the 1,600-year-old Roman masterpiece, the Lycurgus Cup
Using a recipe derived from a fragment of the original glass, the team recreated its remarkable optical behaviour - a colour shift from jade green in reflected light to ruby red in transmitted light
Glass artist and winner of Netflix's Blown Away series 2, Elliot Walker, has brought this effect to life in a contemporary glass sculpture paying homage to its intricate ancient twin using glass made in the Sheffield melting shop
The extraordinary piece will debut at the University’s Festival of the Mind from 6-15 November 2026, before permanent display in the University’s Turner Museum of Glass under lighting that perfectly demonstrates its chameleon characteristics
The remarkable colour-changing effect observed in a famous Roman masterpiece has been successfully reproduced in quantity for the first time in 1,600 years by a University of Sheffield technician.
The Lycurgus Cup, a world-renowned 4th century AD artefact housed in the British Museum, is constructed of ‘dichroic’ glass that shifts from jade green in reflected light to ruby red in transmitted light. This means that depending on where the light source is positioned, observers can see the cup displayed in two distinctive, contrasting colours.
It is one of only 40 surviving glass cage cups from the period and is one of the most complete. The Lycurgus Cup is the only one exhibiting this superb visual effect. Its colours, artistry and almost perfect condition have intrigued and confounded historians and glassmakers alike for centuries. Its exceptional colours and narrative, depicting a mythical Thracian king ensnared in vines because of his misdeeds, led to the artefact being recognised as one of the seven glass wonders of the world by an international panel of artists and conservators in 2022.
While no one knows exactly how its famous colour-changing effect was created, experts believe the Romans achieved it by adding tiny amounts of gold and silver which, under the right conditions, formed layered nanoparticles thousands of times smaller than a grain of sand. Because these nanoparticles are smaller than the wavelengths of light, they absorb light strongly and display vibrant colours depending on their size and shape.
Many have tried to reproduce this dichroic effect with varying success, but establishing a consistent, repeatable recipe has long proved elusive.
After being challenged by Project Manager Christina Metcalfe to replicate it for the University’s LightFest in 2025, experts from the University of Sheffield have successfully reproduced the effect observed in the famous artefact, finally solving the age-old mystery.
For University of Sheffield technician Dr Lisa Hollands, replicating the effect was very much a labour of love.
“I knew that making a glass of this type was likely to be a complex task, as it is not just a case of adding nanoparticles to glass,” said Dr Hollands, from the University of Sheffield’s School of Chemical, Materials and Biological Engineering.
“I’ve studied and worked with glass for over 25 years, so I used the knowledge and experience I’ve gained, coupled with a modern scientific understanding of what I was trying to achieve.
“To start with, I worked with a leading Roman glass expert, Professor Caroline Jackson, to research what was already known about glass of the time and developed a base glass using modern materials to mimic what the Romans might have used. Then came the more difficult part of trying to get small amounts of gold and silver into the glass in the right form.
“Although if the Romans could have seen me experimenting, they’d probably laugh and ask: 'Why does she not know how to make this?'”
After many painstaking experiments with different furnace types, starting materials and oxygen levels - and even the inclusion of sugar - Dr Hollands finally hit upon a glass recipe that appeared opaque green in reflected light and red when a light was shone through it.
The initial piece was exhibited at LightFest, an event held in Sheffield by the Molecular Photonic Breadboards project in partnership with the Universities of Sheffield and Bristol and funded by the Engineering and Physical Sciences Research Council (EPSRC). The project aims to design new materials that harness the power of light for sustainable technologies, vital to the UK's economic success in areas like solar energy, quantum technologies and healthcare diagnostics.
Molecular Photonic Breadboards Project Manager Christina Metcalfe said: “The next step was to commission a piece worthy of paying homage to its illustrious predecessor.
“We approached Elliot Walker, one of the UK’s finest glass artists and winner of season two of Netflix’s Blown Away, who accepted the challenge and was commissioned to create a contemporary sculpture using Dr Hollands’ recipe.”
Elliot said: “It is a very rare thing to have the opportunity to work with glass developed from ancient mixtures and recipes, and it is always a very exciting one.
“You can really get an idea of how the glass makers of the past would have adapted to this sort of glass; it's like shaking their hands.”
This idea of a bridge between the intervening centuries, along with practical considerations, provided the inspiration for the final piece.
“I wanted to keep the sculpture quite classical in form and to carry through the original story of Lycurgus shown on the cup, but we needed a blown element within this to really show the dichroic glass,” Elliot added.
“The piece is a blend of the Lycurgus story and the Farnese Atlas sculpture, with the globe replaced by a cup.”
The piece will be unveiled to the public at the Millennium Gallery as part of the University’s Festival of the Mind from 6 - 15 November 2026. From there, it will be on display in perpetuity at the Turner Museum of Glass in the School of Chemical, Materials and Biological Engineering.
“We set out to create something tangible to help the public understand what is possible when these tiny nanoparticles are embedded in something,” Christina added.
“What Lisa and Elliot have managed to achieve has surpassed all our expectations. The incredible historic narrative really captures people’s imaginations, and I like to think we’ve created something that people will marvel at for years to come.”
While this specific glass will mainly have decorative applications, the scientific understanding gained will feed into new photonic materials and advanced glasses for radioactive waste management.
The project is also linked to Professor Russell Hand’s ongoing work in the Immobilisation Science Laboratory (ISL) within the School of Chemical, Materials and Biological Engineering on immobilising complex nuclear wastes in glass. Understanding the conditions leading to the formation of crystals in glasses is essential in maximising the amount of waste that can be safely immobilised in a glass wasteform.
