Tim Ayers on Medieval Stained Glass

15:00 Tuesday 11th January 2005
BBC Radio 4

SUE COOK: It’s our wonderful heritage of stained glass window making which is the subject of our next query. James Barnam from Bristol asks when and how the use of stained glass windows as a decorative art form developed. And Peter Smith from Jarrow is interested in where the first English stained glass windows were made. A hint of local rivalry in Peter’s email I think. He says he remembers reading in a school encyclopedia that stained glass windows first appeared in his home town of Jarrow. But then when the National Glass Centre opened at Sunderland, in 1998, that distinction was claimed for Monkwearmouth, five miles away. Well we’ll sort this all out now, because Dr. Tim Ayers is a former specialist in this field. He’s the secretary of a British research project into medieval glass, based at the Courtauld Institute in London. Tim, can we start then with Peter’s question, where was stained glass first used in this country? Was it Jarrow, or was it Monkwearmouth?

TIM AYERS: Peter is right that very early window glass was made for the Anglo-Saxon monastery at Jarrow, and you can still see some of it today, reset in the windows of the 7th and 8th century church there. But this glass was dug up by archeologists over the last few decades, and the story is complicated by the fact that a great deal more glass was found at Monkwearmouth nearby, which was a sister monastery that was actually ruled by the same Abbot. And unfortunately we can’t date any of this excavated glass very precisely. There isn’t a carbon 14 dating option for glass. But it was certainly made before both of the abbeys were destroyed by the Vikings in the 860s or so.
SUE COOK: But it’s survived alright? It hasn’t deteriorated?
TIM AYERS: It’s survived remarkably well. The special interest of it though lies in it’s possible connection with a remarkable description that was actually written by a monk of Jarrow in the early 8th century, none other than the Venerable Bede. In his famous Eccesiastical History of the English People. And he writes that in 675 the Abbot of Monkwearmouth, a man called Benedict Biscop, went abroad to Gaul for glaziers to fill the windows of his new church, which he had just founded the previous year. And he says that this was a technique that was previously unknown to the English. So in answer to Peter’s question, it does sound as though Monkwearmouth probably just squeaked in first before Jarrow was founded a few years¬†later in I think 681.
SUE COOK: So where did it actually start being made? Was it in this country, and if so where?
TIM AYERS: No. Well as Bede says, he had to bring these craftsmen over from the Continent. It’s still really an open question where ornamental window glass began. Excavation is continually revealing more glass, which is changing the picture on the Continent. But it’s probably safe to say that a tradition of ornamental window glass was growing up in the late Roman Empire. And the Imperial Church of San Vitale in Ravenna had painted glass as early as the 6th century.
SUE COOK: And what sorts of techniques did they use in those early days?
TIM AYERS: Well the glass excavated at Jarrow is fascinating that in very many ways it anticipates the later medieval technique, the techniquer that lasted right the way through until the 16th century. The material was made from sand and a plant ash, which were then (made) molten together in a furnace, and blown into a sort of sleeve, which was cut down one side, flattened out and cooled down. There was both clear glass and coloured glass. And this glass was then cut up into pieces, and it was held together within a lead framework. And bits of this lead framework were actually dug up in the excavations at Jarrow and Monkearmouth. So this was a mosaic technique, and this mosaic technique carried right the way through until the end of the Middle Ages, as I say, and it was then revived again the the 19th century, in the Gothic Revival.
SUE COOK: So was it princippaly decorative, or was it functional?
TIM AYERS: Well that’s a big question. Clearly glass was being appreciated for its practical value. It kept out the wind, and it kept out the weather, and in a cold wet climate that was very desirable. But certainly in later sources, it’s very clear that glass as a transmitter of light had a symbolic significance. Going right back to the Bible, light was an analogy for the divine, and Christ describes himself in John’s Gospel as the Light of the World. And the Chirch fathers picked up on this, people like Augustine. And that gave windows, window glass and its painted decoration, a very special kind of authority. It’s one reason why medieval patrons and medieval architects struggled to make windows bigger and bigger, ultimately creating great glasshouses like Kings College Chapel for example in Cambridge.
SUE COOK: How much medieval glass still survives today?
TIM AYERS:It survives in great churches like Canterbury Cathedral and York Minster in quite large quantities. But the public perhaps don’t appreciate how¬†many hundreds and probably thousands of churches, parish churches around the country, still retain some of their medieval glass.
SUE COOK: And what is the project you’re actually involved in?
TIM AYERS: Well my project is part of an international project to record all medieval stained glass, not a modest ambition. But we’re over 80 books down the road. In Britain we’ve also got a website, a free website, which sets out general conservation principles that were established by an international committee of conservators, and it includes a digital archive of over 13,000 images, most of them in colour, from over 800 churches.
SUE COOK: Thank you very much Tim Ayres. And there are some lovely pictures from Tim’s project on our webpages, on the BBC Radio 4 website.

Early stained glass – made in Jarrow or Monkwearmouth?