Stained glass has been a Cinderella in English medieval and art historical studies, largely because the material is so little known. Much of what has survived iconoclasts, neglect and the weather is widely scattered, often in parish churches and sometimes broken, difficult to see or hard to photograph. In the middle ages this was a highly prestigious vehicle for a wide variety of images, brightly coloured and brilliantly lit, as the famous surviving ensembles in Canterbury Cathedral, York Minster or King's College Chapel in Cambridge still show today.

Wonder at the miraculous cure of the leper Richard Sunieve by Thomas Becket, c.1215, from a window in the Trinity Chapel, Canterbury Cathedral. Crown Copyright, NMR.
Wonder at the miraculous cure of the leper Richard Sunieve by Thomas Becket, c.1215, from a window in the Trinity Chapel, Canterbury Cathedral. Crown Copyright, NMR.

The Corpus Vitrearum Medii Aevi (CVMA), or survey of medieval window glass, makes the surviving remains accessible. It was founded in 1949 as an international research project, aiming to publish everything that survives, and is still flourishing. In July 2000 a conference was held at Bristol, attended by a hundred delegates from a dozen national committees in Europe and North America. In Great Britain, the project is under the aegis of the British Academy and based in the Conway Library at the Courtauld. Over twenty field workers visit sites around the country, describing the glass, taking photographs and researching the monuments for inclusion in the series. Since 1992 we have produced five volumes, including summary catalogues on the counties of Lincolnshire and Northamptonshire, as well as on two of the grandest windows in York Minster. Now nearing completion are monographs on the parish church of St Peter Mancroft in Norwich and Wells Cathedral.

For the next three years the project is to be funded under the Resource Enhancement Scheme of the Arts and Humanities Research Board (AHRB). This will support not only the on-going programme of publications, but also the exploitation of another resource by which the CVMA brings the medium to a wider public, the national archive of stained glass at the National Monuments Record in Swindon, part of English Heritage. The archive now contains nearly 30,000 images, mostly taken by the former Royal Commission on the Historical Monuments of England. These are photographs of high quality taken often with privileged access to the glass. Several conservation studios have allowed photography on the workbench, permitting the recording of panels in great detail.

Over six months in 1999 the CVMA explored the digitization of this resource in a pilot project, again funded by the AHRB, in partnership with the Centre for Computing in the Humanities at neighbouring King's College. Details of over 3,500 images were entered into a database and the photographs were scanned - they are in two resolutions, one for archive purposes and another for the web. Stained glass is particularly well suited to electronic publication, in that both are dependent upon transmitted light, and we have been very pleased with the prototype website. Thanks to the new funding, we shall go on-line in the next nine months, and we shall maintain the fruitful relationship with King's. Data entry and scanning will continue, with a view to including another nine thousand subjects.

Other digital possibilities will be explored. The scanned images may have wider applications. For example, we have agreed a license for the use of the scanned images in teaching at the Institute. We shall also consider electronic publication for the series as a whole, in consultation with similar projects at the Courtauld and elsewhere and with our international partners - with a view to increasing both scholarly understanding and public awareness of this fragile and beautiful medium.

Dr Tim Ayers