Expert Glazing Techniques in the East Window of the Chantry Chapel of St John the Baptist, Church of St Mary the Virgin, Ewelme, Oxfordshire

Chantry Chapel: East Window (sII) above altar, tombs on the left.

Fig. 1. Chantry Chapel: East Window (sII) above altar, tombs on the left.

The mid-15th-century stained glass in the east window (s.II) of a chantry chapel built for the then earl and countess (later Duke and Duchess) of Suffolk in the church of St Mary the Virgin at Ewelme, a small village about thirteen miles south-east of Oxford, includes exceptionally fine examples of high-class medieval glazing techniques such as ‘jewelling’ and abrading. In 2007 the charitable trust (the Ewelme Trust) which cares for this chapel commissioned the distinguished stained glass artist, Paul San Casciani FMGP, ACR, FRSA, to write a detailed condition report on the glass prior to its conservation by Elise Learner ACR and the team at Chapel Studio, King’s Langley, Hertfordshire.

In the first of two exclusive articles for Vidimus about this glass, Paul explores the sophisticated techniques used by the craftsmen who made four heraldic shields now located in the tracery lights of s.II.

The Donors

The glass was commissioned by Alice Chaucer and her husband, William de la Pole, 1st Duke of Suffolk, probably sometime between 1438 and the mid-1440s. Its original location in the church is unclear.

Alice Chaucer (probably 1404–1475), was the daughter of Thomas Chaucer and Maud Burghersh. Her grandfather was the famous poet and author of The Canterbury Tales, Geoffrey Chaucer (c. 1343–1400) while her grandmother, Philippa (de) Roet, was the sister of Katherine Swynford, the mistress and later the wife of John of Gaunt, Duke of Lancaster.

William de la Pole (1396–1450) was the second son of Michael de la Pole, 2nd Earl of Suffolk and Katherine de Stafford, daughter of Hugh, 2nd Earl of Stafford, K.G. He succeeded to the Earldom in 1415 after his father and elder brother, Michael de la Pole, 3rd Earl of Suffolk, both died during Henry V’s Agincourt campaign. By 1429 William was co-commander of the English forces at the siege of Orléans. After that city was relieved by Joan of Arc he was subsequently captured at Jargeaux and ransomed.

Upon his return to England William quickly became a trusted member of the royal court and its young king, Henry VI (born 1421). As part of his duties for the king, William was given responsibility for the building of Eton College and in 1448 gave a gift of 1000 marks (£666 13s 4d) towards the rebuilding of the chapel. In this capacity he would almost certainly have been familiar with the work of the king’s glazier, John Prudde, (d. 1460/61) who glazed the chancel of the local parish church in 1445–47.

In 1447 William was appointed the king’s Lord Chamberlain responsible for royal estates, Admiral of England, and to several other important offices, thus infuriating rivals at court. He was created Earl of Pembroke in 1447 and 1st Duke of Suffolk in 1448. After the near-complete loss of English possessions in northern France in 1450, William was blamed for the disaster, arrested and banished. On his journey to France his ship was intercepted, and he was murdered, probably at the behest of Richard, Duke of York.

The Chapel

According to Dr John Goodall, the leading expert on the Ewelme complex, the chapel was a ‘pointedly Chaucer foundation….decorated with an overtly self-aggrandizing heraldic display celebrating the family’s connections with England’s high nobility’. It was probably completed by 1438 when the table-top tomb of Alice’s parents, inlaid with their brass effigies and twenty-four enamelled shields was moved into it.

The east window (s.II) contains a collage of 14th- and 15th-century glass apparently arranged by an unknown glazier sometime between 1829 and 1836. The upper tracery lights contain four shields of arms commemorating the families of the Duke and Duchesses and their alliances. Differences in size suggest that they may come from two different schemes, but belonging to the same 15th-century date. The 17th-century Oxford antiquary Antony Wood recorded a set of 12 shields belonging to the Chaucer and De la Pole families in the windows of the church. [Fig. 1]

The Heraldic Stained Glass

The four heraldic lights are s.II A3–A6

Tracery light A3 

Tracery light A3: Shield of de la Pole impaling Stafford.

Fig. 2. Tracery light A3: Shield of de la Pole impaling Stafford.

Described by Peter Newton in his CVMA County of Oxford volume (see Further Reading) as ‘Azure a fess or between three lions faces or DE LA POLE impaling argent a chevron gules STAFFORD.’ The shield is h 220mm; w 175mm. It commemorates William de la Pole’s father, Michael de la Pole (d.1415) and his mother, Katherine, the daughter of Hugh, second Earl of Stafford. (For an explanation of the heraldic terms used here and elsewhere in this article, see the Glossary at the foot of this article – Ed.). [Fig. 2]

This shield has several notable features; traced decorated backgrounds, three painted and yellow stained lion faces, and some exceptionally fine ‘jewelling’.

The blue ground of the de la Pole arms was decorated with a diaper design using watered-down black paint which helps to control and diffuse light glare or halation in the glass. The artist probably used a long-handled brush known as a ‘rigger’ to trace the pattern. The design consists of a mesh of contiguous circles with dotted centres, causing Newton to describe them as resembling ‘a rough pebble pattern’. Under workshop conditions, however, it is clear that the pattern is made of florets or flowerbuds, a motif repeated and seen to better effect in the other heraldic panels discussed in this article.

By contrast to the background painting of the blue glass, the white ground of the Stafford arms incorporates a fern-like foliage design.

The fess (two horizontal lines drawn across a shield) shows the tracing brush outline of the fronds, but note that the bar above it is plain glass, an insert.

The decorated blue base glass provides the ground for three inserts, each with a lion’s face. The upper quarter inserts measures 24mm h (15/16 of an inch) x 23 mm w.; the lower quarter lion’s head: 31 mm h x 34 mm w. The faces have been yellow stained and the traced details of their eyes, mouth and projecting tongue are clearly visible. Although the designs appear fairly standard, the artist would probably have used a small drawing as a common model.

The most interesting feature of the panel is how these ‘lion’ charges (in heraldic terms a bearing such as a crest, badge or insignia and/ or a figure) have been inserted into the blue base glass by the glazier. First, small holes or circles had to be drilled and enlarged, probably by a combination of tools like a bow-drill, a file or some nibbling device which could enlarge and shape the hole. Bow-drills have been used since antiquity. Roughly speaking they consist of a shaft with a metal bit which is spun in reciprocating directions by a tightly wound cord or rope attached to a bow.

Making such holes without breaking the surrounding base glass required great skill and patience. It was also laborious and time-consuming work. Once made, the painted charges then to be leaded and inserted. This also required great skill. Each lion face still has its surround of original lead which holds it in position. To make such inserts, one side of the leaf of the lead (‘H’ in section) had to be carefully opened up so that the insert could be slipped into its aperture, then pressed down and folded back to fix snugly in position. While the two lion faces in the upper quarter of the dexter (the left side of the shield to the spectator) touch the edge of the glass thus providing a little leeway in the fixing procedure, the lower lion’s face sits right in the centre of the blue glass, demanding extraordinary dexterity to insert.

Detail of Tracery light A3.

Fig. 3. Detail of Tracery light A3.

Two other features are worth noting. The first is that the artist has painted a black circle around the leading to highlight the contrast between the yellow light of the lions’ faces and the darker background. The second is the slightly off-centre positioning of one of the charges. It may have been that having inserted the painted face into the base glass it then proved impossible to twist the glass into its desired position without risking breakages. [Fig. 3]

‘Jewelling’ in the Beauchamp Chapel windows. © Y M Pictures.

Fig. 4. ‘Jewelling’ in the Beauchamp Chapel windows. © Y M Pictures.

The technique of drilling holes and inserting new pieces into a base glass is known as ‘jewelling’. Although the technique was used at Augsberg cathedral as early as c. 1120 the earliest surviving examples in English figural glass date from the early 15th century onwards, for example at Tong in Shropshire. Thereafter it became highly fashionable among wealthy elites, such as the crown, top-ranking nobles and ecclesiastics. One particularly lavish scheme incorporating numerous examples of the technique was executed by John Prudde, (the same royal glazier who worked at Eton) for the mausoleum of Richard Beauchamp, earl of Warwick, at St Mary’s Church, Warwick. Professor Richard Marks has called the glittering effects achieved by Prudde in that commission ‘unmatched’ within the British Isles (see Further Reading, Marks). Although there is no evidence that Prudde was responsible for the Ewelme glass, the quality of the jewelling undertaken in the Suffolks’ chantry chapel glazing confirms the employment of highly skilled craftsmen. The couple certainly had both the money and the contacts to hire the best. According to Goodall, after her husband’s death Alice commissioned a tomb for him from the same craftsmen who had previously worked on the Warwick monument. [Fig. 4]

Tracery Lights A4 and A5

Even more impressive examples of ‘jewelling’ can be seen in the slightly smaller shields in tracery lights A4 and A5.

Shield of John of Gaunt, Duke of Lancaster impaling Neville. Tracery Light A5.

Fig. 5. Shield of John of Gaunt, Duke of Lancaster impaling Neville. Tracery Light A5.

Newton describes them as ‘Quarterly 1, 4 azure three fleurs-de-lis or FRANCE 2, 3 (gules) three lions passant guardant in pale or ENGLAND a label of two points ermine JOHN OF GAUNT, DUKE OF LANCASTER impaling gules a cross saltire argent NEVILLE’ (h. 198mm h x 165mm w). The shields represent Chaucer ancestry and alliances. As mentioned earlier, Alice’s grandmother, Philippa de Roet, was the sister of Katherine de Roet [Swynford] the third wife of John of Gaunt, Duke of Lancaster and aunt to their daughter, Joan, who married Ralph Neville, Earl of Westmorland d. 1425. The character of Westmorland in William Shakespeare’s play Henry V is based on Neville. [Fig. 5]

The top left of the quartering of this shield shows the T-shaped label (with an old repair) painted with tiny ermine tails surrounded by three very small charges, fleurs-de-lis. The glazing of the top two bearings flanking the horizontal bar (label) needed incredible precision to fix, and the lower one sits in the middle of its blue ground, its shape having been drilled out using the same method as the lions’ faces. Below right is a similar quartering. All the fleur-de-lis inserts have surrounds of original lead. The upper quarter inserts measure 13mm h (just over half an inch) x 10mm w; the lower quarter, 13mm h x 16mm w.

Tracery light A5 on the bench.

Fig. 6. Tracery light A5 on the bench.

The technical achievements in these miniscule insertions are to be marvelled at, both the size of the actual fleurs-de-lis and the respective holes they have been glazed into. [Fig. 6]

Again, diaper patterns have been traced onto the surrounding backgrounds. The blue and ruby backgrounds have contiguous floret patterns. A long leaf with a serrated edge has been traced on the saltire cross, except for the upper right arm which is a modern plain glass insert.

The two depictions of the three lions passant (i.e, with the right or dexter leg raised) highlight a common problem of trying to reproduce heraldic tinctures or colours in stained glass. John of Gaunt’s coat of arms showed three yellow lions against a red background – easy to copy in panel painting or in dyed /embroidered textiles of the period but impossible to recreate in the stained glass at Ewelme. Why? Look at the shapes of the lions – small and complex. Now imagine what the medieval craftsman had to do to achieve the desired heraldic effect. The background to the lions had to be red (gules) or ruby glass. As readers will know, because ruby glass was made from a very heavy colourant, copper oxide, it had to be ‘flashed’, or coated to a side of white glass if it was to have any translucency. One advantage of this process was that if the ‘red’ coating could be removed by an ‘abrading’ process, such as scraping or grinding, probably aided by a gritty compound, and the white glass exposed, painters could achieve two colour effects in the same base glass, e.g. red and white, or red and yellow if the plain glass was stained. At Ewelme it was impossible for the glaziers to abrade ruby glass to the requisite shape for such small and complex designs as the three lions passant.

As a result the painters used plain glass as the background, notwithstanding its heraldic inaccuracy. The outlines of the lions were traced (most of the lines have eroded) and then yellow stained. Unable to use a red ground, the white glass was painted with a fine traced cross-hatching to provide both a light diffusing background for the charges and to emphasis the colour and visual impact of the lions.

When the antiquary and heraldic expert, Edmund Arnold Greening Lamborn (1877–1950) described the Ewelme glass in 1949 (see Further Reading) he assumed that the absence of a red background in this panel meant that the colour must have decayed. Peter Newton understood the problems better – hence the reference to gules in brackets in his cataloguing of the glass.

Tracery Light A 6 

Roet impaling Burghersh. Tracery light A6.

Fig. 7. Roet impaling Burghersh. Tracery light A6.

The final tracery light contains a successful example of abrading for heraldic purposes. Newton described shield A6 as: ‘Gules three catherine wheels or ROET FOR CHAUCER impaling argent a chief (gules) over all a lion rampant queue fourcheé BURGHERSH’ (h. 221mm h x 178mm w.) . The shield represents Alice’s parents. Her father had been born in 1367 and in 1399 was made Constable of Wallingford castle, an important crossing over the Thames. He was speaker of the House of Commons in 1414. Rather than display the Chaucer arms he adopted those of his mother, Philippa, the daughter of Sir Paon Roet. He married Maud, the daughter and heiress of Sir John Burghersh of Ewelme through whom Alice brought the manor in marriage to William de la Pole. [Fig. 7]

A6 Scratch marks on the edges of the Roet wheel shapes.

Fig. 8. A6 Scratch marks on the edges of the Roet wheel shapes.

The three wheels have been made by rubbing away the ruby flash to reveal the clear glass beneath. This would have been painstaking work. A stain has then been applied and fired to give the wheels a yellow hue. Examination of the reverse side of the panel on the bench clearly shows some scratch marks made by a sharp abrading tool that has slipped beyond the circumference of the circles. The circular shapes were much easier to make than the elaborate design of a lions’ passant as discussed above. The ruby glass has been decorated with the same floret pattern as described in A3. [Fig. 8]

The other important feature of this panel is the painting of the lion. His forked tail is particularly striking. The trace line depicting the outline with flourishes of fur on legs and tails is fluent and expressive as the painter has varied the pressure on the brush to achieve an eloquent line of varying widths, the sign of an experienced artist. Shading within the body of the lion has been achieved by the application of a thin film of paint modified with a badger brush to control the light. This technique is seen all over the commission and lends a sophistication to the depiction of all the main subjects. However, there are two puzzling elements in this shield. The line round the three wheels is hard and has suffered no erosion whatsoever. The paint appears black and without shine, suggesting this is a reinforcement or repainting of a later period, lightly fired for permanence. Equally curious is the carefully painted horizontal line across the lion’s middle, but going behind its body – again, in black pigment, contrasting with the brownish hue of the original paint. Maybe this was done at the same time as the redefinition of the wheels, but in this case the reason is obscure.

Paul San Casciani FMGP

All photos except Figs. 1 and 4 were taken at Chapel Studio Herts and are © Paul San Casciani of Paul and Paula San Casciani Stained Glass Consultants. Images reproduced by kind permission of the Ewelme Trust.

In a future issue of Vidimus Paul will discuss the sophisticated glass painting techniques used by the medieval artists responsible for a series of roundels at Ewelme depicting heraldic beasts, lions and yales.

Further Reading

  • Newton, P. assisted by Kerr, J., The County of Oxford: A Catalogue of Medieval Stained Glass, Corpus Vitrearum Medii Aevi Great Britain, Volume One, the British Academy for Oxford University Press, 1979, especially pp. 91–96


  • Chitty, H., ‘John Prudde, king’s glazier’, Notes & Queries, 12th ser., 3, 1917, pp. 419–21
  • Goodall, J. A., God’s House at Ewelme: Life and Devotion in a Fifteenth-Century Almshouse, Ashgate Publishing, 2001
  • Greening Lamborn, E.A., The Armorial Glass of the Oxford Dioceses 1250–1850, Oxford University Press, 1949
  • Marks, R., Stained Glass in England During the Middle Ages, Routledge: London, 1993, especially pages 38–39
  • Newton, R., ‘Medieval methods of attaching ‘Jewels’ to Stained Glass’, Stained Glass, Spring 1981, pp. 50–53
  • Saul, N., English Church Monuments in the Middle Ages, Oxford University Press, 2009, pp. 297–299

Glossary of Heraldic Terms Used in this Article

  • Argent – heraldic term for silver or white
  • Azure – heraldic term for blue
  • Bearing – armorial bearings or ensigns
  • Blazon – written description of armorial bearings
  • Charge – a bearing or figure represented on a shield
  • Chevron – upturned V
  • Cross saltire – a cross in the shape of an X
  • Dexter – right as opposed to left (sinister)when describing charges on a shield. However all blazon assumes that someone is standing behind the shield. Thus the dexter (right) side of the shield will appear as the left side to the spectator.
  • Ermine – black tails on white
  • Fess – two horizontal lines drawn across a shield
  • Guardant – a beast looking at the spectator rather than seen in profile
  • Gules – heraldic term for red
  • Impaling – two coats of arms side by side in one shield
  • Label – horizontal bar of two points
  • Lion rampant queue fourcheé rampant means standing on one leg; queue is with tail and fourcheé /sometimes forchy means that the tail is forked
  • Or – heraldic term for gold or yellow
  • Pale – a vertical stripe in the middle of the shield
  • Passant – a four-legged beast with the dexter foreleg raised as if walking

A Note About the Author

Paul San Casciani FMGP, ACR, FRSA began his training in 1950 at James Powell Stained Glass Studio (Whitefriars Glass), specialising in traditional glass painting. He spent some years at the Carl Edwards Studio in the Apothecaries Hall, City of London before becoming an independent designer-maker of stained glass in 1971. In 1998 he founded Paul San Casciani Stained Glass Consultants with his wife Paula. Their Conservation Programmes in collaboration with Chapel Studios have included Duke Humfrey’s Library, The Bodleian, University of Oxford; St Alban’s Cathedral; Middlesex Guildhall, Parliament Square London, now the Supreme Court; Horace Walpole’s Stained Glass Collection, Strawberry Hill, Twickenham and the Sir John Soane Museum, London.

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