Do you see the man dressed in the yellow tunic with a green cape on the picture? His name is Eilward and he is big trouble. In this picture, he is being accused of robbery by his neighbor Fulk. Here’s how the story goes: apparently, Eilward owed Fulk some money and did not want to pay. One day, they were both in the same tavern and they got into a drunken fight about the debt. Eilward got mad and decided to invade his creditor’s home and steal something to teach him a lesson. The problem is that Eilward was caught in the act, and Fulk brought the problem to the authorities.
Eilward was condemned, his eyes were plucked out and his genitals cut off. But he was a believer in the miracles of St. Thomas Beckett, and prayed hard for help.
He had a vision where he was visited by St. Thomas, who touched his eyes with a staff and restored his eyesight. Eilward was so happy that he decided to go to Canterbury Cathedral to worship the shrine of St. Thomas Beckett in thanks to the miracle he experienced.
On his way there, he met with many people who were surprised to see him so well. The panel above shows Eilward pointing to his own eyes, telling someone on the street that a miracle by St. Thomas restored his vision. One of his colleagues is still very skeptical and points to Eilward’s crotch. Did St. Thomas give that back too?
This is one example of the many miracle stories depicted on the stained glass windows of the Canterbury Cathedral. These windows once served to teach lessons to visitors of the place, many illiterate, who came from all over Europe to pray at the shrine of Thomas Beckett. Among the themes depicted on the windows were biblical stories and Christ’s genealogy. In fact, the oldest window that remains shows a picture of Adam digging in the Garden of Eden, the first figure in Jesus’s genealogy.
In the early modern era, with the advent of Protestantism and the Reformation, much religious art was destroyed by iconoclasts, including many medieval stained glass windows. All throughout Northern Europe, many reformers attacked images, statues, and other art work that showed images of God, because they believed these constituted idolatry, which the Ten Commandments strictly prohibited. Canterbury Cathedral was also targeted by iconoclasm, of which one of the most important instances was the dismantling of St. Thomas Beckett’s shrine in 1538 by order of Henry VIII. In the first half of the seventeenth century, Puritans also did a lot of damage to the religious images, including to sculptures and medieval stained glass panels. Adding to that destruction we have the action of bombs during the Second World War, environmental effects, vandalism, and neglect. Today, what remains of these historic panels is under the care of the Cathedral Conservation Studios.
One of the important differences between a conservation studio and a restoration studio is in the way each approaches the care of stained glass. Rather than simply improving the appearance of the object, or replacing what is damaged, the main goal of a conservation studio is to maintain the integrity of the historical object for as long as possible. Any change must be reversible and the original materials are kept until there is no other option possible. This differs widely from the restoration techniques used by the Cathedral personnel of the 19th century, whose restoration efforts went as far as replacing broken panels with entirely new copies of the designs.
Léonie Seliger, head of Stained Glass Conservation, took TEEME on a visit of the scaffolding that is currently covering the South Oculus window of the cathedral, to show us how the conservators work. This window is currently undergoing renovations to have protective glazing installed, which will help shield the historic glass from the weather and pollution. Observation of the North Oculus had already indicated that having protective glazing might be beneficial, but a study conducted over a period of 18 months by TC Associates Ltd, environmental monitoring specialists, served as confirmation of the anecdotal evidence:
“No condensation was measured on the protected historic glass, while the unprotected stained glass was regularly dripping with water on the internal as well as the external face (there obviously from rain water). At no time did the protected glass reach higher surface temperatures than the unprotected glass. During cold periods, the surface temperature of the unprotected glass dropped far more than that of the unprotected glass. This means that the amplitude of temperature difference is significantly reduced through well ventilated protective glazing, reducing thermal stress on historic glass and lead. Liquid water on the historic glass is now completely absent, and since water is the primary agent of corrosion of glass, the elimination of water on its surface will vastly reduce the rate of corrosion.”
Once we got up in the scaffolding, 20 meters above ground, the first thing Ms. Seliger made us notice was a huge, heavy iron grill that covers the ferramenta of the South Oculus. Engineers used to think this structure was from the 19th century, probably an addition to provide support to the ferramenta against wind and deformation. However, the installation of the scaffolding in 2006 allowed them to inspect the grill from up close, and an expert on medieval ironwork confirmed that it was all part of the same ironwork dating from the late 12th century. The way the metal was weaved together meant that this grill had to have been installed during the construction of the building, and not centuries afterwards. To open such a large round window in the wall was a challenge for builders in the 12th century: having the hole meant that the building structure was weakened. This heavy iron frame is the solution the builders came up with; it not only serves as support for the ferramenta artwork (more on this in a moment), but it also helps sustaining the wall of the cathedral. The curious fact is that such space frames were thought to be an architectural invention of the 19th century, but the South Oculus at Canterbury Cathedral shows that 12th century builders knew quite a bit about civil engineering.
Another important function of the wrought iron grill was to help give structure to the ferramenta, the metalwork that supports the stained glass. Even though the ferramenta was made of metal, its delicate design did not provide enough support in itself, so a structure frame was crucial for handling the panel during installation. Without this added support, the panel would flap over like a sheet of paper and break. Note that ‘during installation,’ in this case, means in the year 1180.
Once we got down from the scaffolding, we had a short presentation about the South Oculus conservation project. After that, we headed to the Stained Glass Studio, where much of the delicate conservation work is done. It is there that the conservators bring the stained glass panels to be cleaned, repaired, and stored until they are ready to go back on the window. It is also there that most of the efforts to document the conservation process are done. Keeping detailed records of any work in the historic panels is considered today one of the most important aspects of the studio’s work. “It is impossible to foresee what future generations might want to learn from the glass, so efforts are made to cover all aspects of the work and the materials.”
The studio not only works with the conservation of historical stained glass, but also receives commissions for new art work. Ms. Seliger showed us how a panel is made, from the design to the cutting and fitting into the lead work. Unfortunately, we did not have a chance to take a look at the process of firing the glass, but we did peek into the microscopes to see some of the decay in the stained glass from really close. One of the conservators working at the studio showed us the painstaking work of cleaning a medieval panel with a soft brush. In order to avoid damaging the glass, she has to gently and repeatedly brush it, trying to remove the corrosion without actually using force. Placing the panel on a luminous table, we could see through transmitted light some of the more severe damage that the glass had suffered.
Photo credits: Jon Oster
Collinson, P., Ramsay, N., Sparks, M. A History of Canterbury Cathedral,
Oxford University Press, p. 154.