Scene from the Life of Thomas Becket (c. 1190–1205), a stained glass medallion from England’s Canterbury Cathedral, has always commanded attention. Part of a window depicting the saint’s life, the medallion was originally installed in the devotional space surrounding Becket’s shrine, known as the Trinity Chapel. Like all stained glass works there, it would have had a special resonance for pilgrims who came to venerate and celebrate Becket.

Centuries later, the medallion is part of the Harvard Art Museums collections, on permanent display in the medieval art gallery. It’s also the focus of ongoing conservation and technical analysis.

“Stained glass is fascinating to study because every piece has a story behind it,” said Charlotte Gray, who studied the window when she was serving as an Agnes Mongan Curatorial Intern in the Division of European and American Art (from 2010 to 2011). A Ph.D. candidate in the Department of History of Art and Architecture, Gray was awarded a Baird Fellowship for travel to Canterbury to study the window’s original environs.

Last summer, Gray, along with Katherine Eremin, the Patricia Cornwell Senior Conservation Scientist at the Straus Center for Conservation and Technical Studies, spent three fruitful days at Canterbury. The results from their research are still being reviewed, but the experience has already enriched conversations and activities focused on the window.

The Window’s Early Life

Becket, the archbishop of Canterbury, was famously murdered inside the church in 1170 by knights of King Henry II. Buried inside the cathedral and canonized, with a shrine constructed in the Trinity Chapel, Becket became something of a cultural phenomenon. His life and death inspired countless works of literature (such as Chaucer’s The Canterbury Tales) and art. In the Trinity Chapel, ornate window panels, designed by some of northern Europe’s finest glass artisans, were installed to pay homage to Becket—including the one in Harvard’s collection.

Most panels show Becket in posthumous scenes; Harvard’s medallion, however, features Becket (the fourth person from the left) accepting an oath or receiving a message (historians aren’t sure exactly what is depicted). The window is significant also because it includes Edward Grim (the second individual from the right), Becket’s contemporary biographer and an eyewitness to his martyrdom.

During the ensuing centuries, Scene from the Life of Thomas Becket survived various threats, including attacks on the cathedral by 16th- and 17th-century iconoclasts such as Henry VIII. By the late 19th century, many of Canterbury’s medieval windows were restored or replaced by more modern panels. Scene from the Life of Thomas Becket was likely also removed in that period. It was held by private collectors for about 25 years before it was purchased in 1924 for Harvard by Arthur Kingsley Porter, a professor and medieval art historian.

Conservation and Examination

The medallion has received special attention in recent years, particularly as it was prepared for display in the renovated Harvard Art Museums. Conservators and curators considered a variety of approaches for treating the object, but ultimately decided on a method that would “recover something closer to the medieval version of the window,” said Angela Chang, assistant director of the Straus Center and conservator of objects and sculpture.

In consultation with museums staff, independent glass conservator Mary Clerkin Higgins disassembled the object’s more than 260 pieces of glass. This enabled Straus Center scientists, including Eremin and Georgina Rayner, the Andrew W. Mellon Postdoctoral Fellow in Conservation Science, to analyze each piece of glass in order to determine its composition and likely age. The results fed lengthy discussions and helped the team map out how the window had been restored previously. Most of the pieces were medieval, though not all of them would have been original to the window: it was relatively common for cathedral glass restorers to replace broken pieces with spare pieces of medieval glass, rather than use new material.

Close examination of the lead cames (the metal bars supporting and outlining individual glass pieces) suggested that they dated to the late 19th century, around the time the window was removed from the cathedral. In addition to covering some painted details on the glass pieces, the configuration and size of the cames added during previous restorations caused some distortion to the original arrangement of the glass pieces. In efforts to restore the medallion to its original appearance, Higgins replaced the cames and added a decorative glass border. A custom-fitted LED sheet was also added to illuminate the glass from behind, activating the medallion’s rich, vibrant colors even in the gallery setting.

Hands-On Analysis

On their trip to Canterbury, Gray and Eremin visited the cathedral’s Stained Glass Studio, whose eight glaziers and conservators care for the building’s 1,200 square meters of stained glass. They were able to climb scaffolding to scan windows with a portable XRF (X-ray fluorescence) analyzer, collaborating along the way with Kelly Domoney, of Cranfield University.

“We were looking at all aspects of the glass, including weathering and other condition issues, chemical composition, painting style, leading, and evidence of historic restoration practices,” Gray said.

The Stained Glass Studio also shared lighting equipment and microscopes, and provided updated conservation reports on other glass panels related to Harvard’s medallion. “It was a wonderful view into how medieval cathedrals are really living monuments, with artworks cared for, discussed, and exhibited in contexts quite different from those in which most medieval art in the United States is displayed,” Gray said.

Conversations Continue

Back at Harvard, Gray and Eremin began the work of comparing data from their trip with information from Higgins’s conservation of Scene from the Life of Thomas Becket. This work continues, as do the pair’s efforts to educate others in technical and art historical aspects of medieval stained glass.

Together with Elizabeth Pastan of Emory University, Gray and Eremin held a stained glass study day at Harvard in April for undergraduate and graduate students and glass artists. They have also given gallery talks about the work.

For Gray, the medallion is more than simply a fascinating case study; it’s literally a window into the past. Because most hues in stained glass don’t fade over time, “we see the colors exactly as someone in the Middle Ages would have seen them,” she said, “which I find a really beautiful idea.”