Coventry Cathedral’s medieval glass archive opens online

By Grace Kim

Thirty wooden crates contain thousands of fragments from Coventry Cathedral’s shattered medieval windows. The broken glass forms an internationally significant collection that, for the first time in almost 90 years, will be available for public viewing through the Bloomberg Connects app in November.

The cataloguing and photography programme was led by Laura Atkinson, a stained-glass conservator (a specialist in caring for historic glass). She described the collection’s quality as “stunning” and said the surviving work is attributed to John Thornton of Coventry, a master glazier (a stained-glass maker) who also created the Great East Window of York Minster.

For decades after the Luftwaffe (German air force) destroyed Coventry Cathedral in 1940, broken glass was packed into those crates and stored in a cellar. The windows had first been smashed during the Reformation, then dismantled for safekeeping before the second world war.

Cathedral authorities knew the remnants held spectacular 15th-century glass, but five turbulent centuries of loss left the scale of survival uncertain. The programme addresses that gap by photographing and cataloguing thousands of pieces.

What does opening the archive change for researchers?

For conservators and scholars, the practical change is searchable access to individual fragments that storage had kept out of view. Atkinson sees stylistic parallels between Coventry’s glass and windows at Westminster Abbey and Canterbury Cathedral. She said comparing the sites could show how medieval craftspeople moved among cathedrals and across different phases of work.

Some pieces remain small and individual. Others had been reassembled at some point after the Reformation into a patchwork panel that only hints at its original scenes. Andrew Hines, head of heritage and interpretation at the cathedral, described the result as a “medieval jigsaw puzzle.”

Atkinson said the fragments include biblical and crucifixion scenes, along with donors who funded the windows and appear kneeling in prayer. The glass also carries images she described as whimsical animals and beasts, precious gems and jewelled fabrics.

Atkinson explained that medieval glazers scratched away the glass surface to form a small opening, then inserted coloured glass to represent jewels. She said the procedure took a long time, had a high failure rate and produced exceptionally costly, high-end work that required immense skill from the original makers.

Human faces provide the collection’s strongest emotional pull, Atkinson said. She said viewers can feel a connection with painters from the past, while the apparent self-portraits suggest that medieval artists often drew themselves.

The cathedral was famously rebuilt in the 1960s. Hines said the collection had long been an open secret among experts, who regarded it as a world-class medieval glass archive. Poor storage, however, had concealed both its importance and its scale.

Hines said the project has made conservation (repair and preventive care), research and public engagement possible in a way the cathedral could not manage before. Atkinson said the archive opens new avenues for further research, including the possible use of artificial intelligence (AI) tools to reconstruct the themes of the original 15th-century windows.

The completed cataloguing project received support from the World Monuments Fund. The scanned collection will initially be available for public browsing in November, coinciding with Remembrance season. The release will let people in Coventry and farther afield examine the fragments virtually.

Coventry Cathedral plans to establish a permanent digital archive in future. That would extend access beyond November. Atkinson said AI may help reconstruct the lost window schemes; for now, the digital catalogue supplies the evidence on which any reconstruction would have to rest.