STAINED GLASS

AGENTS

STAINED GLASS

OF THE MIDDLE AGES IN
ENGLAND AND FRANCE

PAINTED BY
LAWRENCE B. SAINT

DESCRIBED BY
HUGH ARNOLD

The Cathedral verger, conducting his flock of tourists round the building, while giving them plenty of really interesting and valuable information about it (for the verger of to-day is a different man from his predecessor, and is often very intelligent and well informed), remarks briefly, "The glass is of the thirteenth century"—or fourteenth or fifteenth, as the case may be; the procession gazes carelessly at it, and passes on. Yet from out of that dazzling and glowing labyrinth of coloured jewels a past age is speaking far more articulately, if one stops to unravel the message, than ever in stone or wood, and it is for those who can be induced to take that second look which will be followed by a third and a fourth and many more that I have written this book.

It is impossible in a book of this size to give an adequate review of all the important windows even within the limits of place and time which I have set myself. I have therefore chosen for study certain typical windows in each century, and have written about them some of the things which interest me and which, I hope, will interest others.

The work of the countries and period I have chosen is of course the most important of all. There is beauty, it is true, in much Renaissance work (only a prig could resist the gaiety and charm of the windows of St. Vincent at Rouen), but it is for the most part beauty achieved in spite of, and not through, the material. There is beautiful mediæval work in Germany and Italy, but the Germans, till the Renaissance, clung to a rather lifeless and archaic convention, and the Italians were hampered by their greater knowledge of painting. The art has found its noblest expression in the work of the great school which for nearly the whole of the Middle Ages was common to France and England.

There is especial reason why we English should study the work of our own mediæval glass painters. They are the chief representatives of our primitive school of painting. It is true that there are English manuscripts in the museums, and there are the painted rood screens of Norfolk, including the superb example at Ranworth, and there is the portrait of Richard II. at Westminster; but of the painting which must once have covered the walls of our churches, there is little left but patches of faded colour clinging here and there to the plaster, and the occasional dim outline of a figure. Of our glass, on the other hand, in spite of four hundred years of destruction, a considerable quantity remains, and is worth far closer study than it has ever had.

I must gratefully acknowledge the help I have had from my brother, Mr. T. K. Arnold, especially in writing of the Canterbury glass of which he has made a very close study. My thanks are also due to Mr. Noel Heaton for information on the chemical composition of glass.

The publishers are fortunate in having been able to reproduce, for the illustrations, the very beautiful coloured drawings of Mr. Lawrence B. Saint, which are now in the Victoria and Albert Museum.

H. A.

CONTENTS

ILLUSTRATIONS

I
THE MAKING OF A WINDOW

I
THE MAKING OF A WINDOW

The making of stained-glass windows is one of the arts which belong wholly to the Christian Era. Its traditions do not extend back beyond the great times of Gothic architecture, and it is to the work of those times that the student must turn, as the student of sculpture and architecture turns to that of the ancient world, to learn the basic principles of the art.

In the Middle Ages stained glass formed an important part, but still only a part, of that interior colour decoration without which no church was considered complete; but in spite of its fragile nature it has on the whole survived the attacks of time, the fury of the Puritan, the apathy and neglect of the eighteenth century, and the sinister energies of the nineteenth-century restorer better than the painting which once adorned the walls and woodwork, and for this reason has come to be considered in these days as peculiarly appropriate to churches. So much so, indeed, that whereas I have sometimes found in country parishes a certain amount of opposition to any attempt to revive wall-painting as savouring of popery, no such feeling seems to exist with regard to coloured windows.

The process.

Stained glass is not one of the arts in which the method of production reveals itself at the first glance. Indeed, so few people when looking at a stained-glass window, whether a gorgeous and solemn one of the thirteenth or fifteenth century, or a crude and vulgar one of the nineteenth, realize the long and laborious process by which the result, good or bad, has been obtained, that a short description of that process as finally perfected some five hundred years ago may not be out of place here.

One hears it so often spoken of as "painted glass"—Mr. Westlake calls his book A History of Design in Painted Glass—that it is not surprising that there should be a good deal of misconception on the point. It must be clearly understood then that the colour effects which are the glory of the art are not directly produced by painting at all, but by the window being built up of a multitude of small pieces of white and coloured glass—glass, that is, coloured in the making, and of which the artist must choose the exact shades he needs, cut them out to shape, and fit them together to form his design, using a separate piece for every colour or shade of colour.

In twelfth and thirteenth century windows many of these pieces are only half an inch wide and from one to two inches long, and few are bigger than the palm of one's hand; so the reader can amuse himself, if he wishes, in trying to calculate the number of pieces in one of the huge windows of this date in the Cathedral of Canterbury, York, or Chartres, and the labour involved in this, the initial stage of the process.

When the window is finished these pieces are put together like a puzzle and joined by grooved strips of lead soldered at the joints, just as any "lattice" window is put together (and until glass was made in large pieces this was the only way of filling a window); but before this is done the details of the design—features, folds of drapery, patterns, and so on—are painted on the glass in an opaque brownish enamel made of oxide of iron and other metals ground up with a "soft" glass (i.e. glass with a low melting-point). This is mixed with oil or gum and water in order to apply it, and then the glass is placed in a kiln and "fired" till the enamel is fused on and, if well fired, becomes part of the glass itself. This is the only "painting" involved in the production of a stained-glass window, and its effect, in the hand of an artist, besides enabling him to express more than could be done merely with glass and lead, is to decorate and enrich what would otherwise be somewhat crude and papery in effect.

The two parts of the process.

The process thus consists of two parts. The cutting and putting together of the glass is called glazing, and it is this that gives the window colour; while the enamel work is spoken of as painting, and gives detail, richness, and texture.

I shall presently show that the glazing and painting are really two separate crafts, having separate origins and development, and that stained glass as we know it, or as it should be called in strict accuracy "stained-and-painted" glass, is the product of their union.

There is another method, far inferior in the beauty of its results, by which pictures can be produced in glass, which is to paint on white glass with transparent coloured enamels. As, however, this method was not used till the seventeenth century, and is now once more almost wholly abandoned, it does not concern us here.

The softness of lead which makes it the only practicable metal for joining pieces of glass of complicated shapes, has the disadvantage that a stained-glass window when leaded up has a considerable degree of flexibility, and, if held by the edges alone, would be quite unable to resist the pressure of the wind, which on a big window is enormous,—think of the power even of a fresh breeze on a boat's sail.

The iron-work.

It would not even be able to support its own weight for long, and so it follows that it must be held up by a system of short metal bars fixed firmly into the stone-work. Naturally the design of the window must be so arranged that these bars either do not interfere with it or form an integral part of it. In early windows, especially those of the twelfth and thirteenth centuries and even to some extent in those of the fourteenth, the bars are sufficiently important to form the governing factor in the design.

It must not be thought that stained glass loses in beauty by the presence of these black lines of lead and iron. On the contrary it gains enormously. Large pieces of unrelieved colour in windows are thin in effect and trying to the eye, which needs the continual contrast of the solid black of the lead all over the window to enable it to appreciate the colour and brilliance of the glass. The painting when rightly used is directed to the same end, for it may be said that the smaller and more divided the spaces of clear glass, the more brilliant and jewel-like is the effect.

Silver stain.

To the rule that a separate piece of glass must be used for every change of colour, there are, in later work, two exceptions. The most important, which was discovered early in the fourteenth century, is the use of silver stain. It was then found that if white glass is painted with a preparation of silver—either oxide or chloride of silver will do—and then "fired" in the kiln used for the enamel painting, it will be stained a clear and indelible yellow, varying from pale lemon to deep orange, according to the strength of the painting.

Abrasion.

The other exception was Abrasion, effected by the use of what is called "flashed" glass. Flashed glass is glass so made that instead of being coloured all through, it consists of a thin film or "flash" of colour on a backing of white. With this glass it is possible to chip with a burin, or grind away, the coloured film in places (we do it now with hydrofluoric acid) so as to get white and colour on the same piece of glass.

In the Middle Ages only red and certain shades of blue were made in this way, so the use of the process was very much restricted. The invention of silver stain, on the other hand, by enabling the artist to decorate his white glass and make it interesting, led him at once to use a larger quantity of white in his window, and so, as will be seen later, had a considerable influence on design.

These, however, are the exceptions which prove the rule, and, broadly speaking, a stained-glass window must consist, to the eye, of flat patches of colour, large or small, worked on with dark monochromatic line work and shading. These patches of colour must each be separated from the next by a black line—the leading—varying from a quarter to half an inch in thickness, and crossed at intervals by still thicker black lines—the iron bars.

Limitations of the art.

It follows from this that anything like illusion is impossible in stained glass, and no artist with any sympathy for the medium would attempt it. Unwise persons in decadent times have wasted much ingenuity in the endeavour, but the result has always been disastrous and ridiculous. Apart from its higher mission,—the expression of ideas and emotions,—which it shares with every other branch of art, the mission of stained glass is to beautify buildings and nothing else. It is the handmaid of architecture, and can only justify itself by loyal service of its mistress. The ideal of the stained-glass artist must not be a picture made transparent, but a window made beautiful.

Let no one suppose, however, that the artist is hampered by these limitations on the higher side of his work. On the contrary, they set him free to tell his story his own way. Ruskin—poor Ruskin, out of date, ridiculed, forgotten—pointed out long ago, in writing of Giotto's frescoes, the advantage which the pure colourist has over the chiaroscurist in his power of telling a story. In our times the fact has been rediscovered with a flourish of trumpets by the Post-Impressionists. I have no great enthusiasm, I confess, for the way in which they have carried out their principles, but I do know two perfect tellings of the story of the Creation. One is in mosaic on the ceiling of the narthex of St. Mark's at Venice, and the other is in the upper part of the east window of York Minster; and in each case the language used consists of flat forms and colour only.

II
THE BEGINNINGS OF STAINED GLASS

II
THE BEGINNINGS OF STAINED GLASS

I have said that stained-glass work is the product of the union of two crafts, the glazier's and the enameller's. The glazier's work being the groundwork of a window, I will take it first.

Glass-making.

What, to begin with, is glass? It is sand melted and run together. The best sand for the purpose is that which is most largely composed of the substance called silica, such as sand formed of powdered quartz, or flint. For some reason, the silica when melted does not recrystallize on cooling as might have been expected, but forms an even transparent substance, plastic while still hot. Think of the tremendous effect this one natural fact has had on the architecture, dress, and, probably, the physique of the nations of northern Europe.

Given sufficient heat, glass can be made by this means alone, but the heat required is so great that it has only been done in recent years for special purposes by means of the electric furnace. Failing this, the sand must be induced to melt at a lower temperature by means of a flux, for which either potash or soda may be used, and to which lime or lead must be added, to enable the glass to resist moisture. (Theophilus, describing the process in his Treatise, certainly no later than the thirteenth century, recommends the use of beech twigs calcined in an earthen pot, whence the name "Pot-ash.")

Colouring.

Glass may be coloured or "stained" while in a molten condition by the admixture of various substances, mostly metals, gold, copper, manganese, and so on, the result depending on the temperature to which it is subjected and on the exact composition of the glass as well as on the colouring matter used.

Blowing.

Glass is made into vessels, as most people know, by "blowing." The workman takes a dab of molten glass on the end of a long metal pipe, and putting his mouth to the pipe blows the glass—soap-bubble fashion—into a hollow bulb. Then by a rapid and dexterous series of alternate and repeated heating, blowing, and spinning, and manipulation with tools, most fascinating to watch, he shapes it into the form required. If a flat sheet be required for window glass it may be run out flat when liquid, or blown as described above, and worked into a cylindrical form, split open, and unrolled. This is called "muff glass." But glass can also be formed, by rapidly spinning it while soft, into a large flat disc, called a "crown," and is then known as "crown glass." It was by these last two methods, the "muff" and the "crown," that all the material of the windows we have to consider in this book was made.

Cutting.

When cold, the sheet or disc of glass may be cut to the shape required, either, as in the old days, by running a hot iron slowly along the proposed line of fracture, in which case a crack will follow the iron, or by scratching it with a diamond and then bending it so as to break along the line of the scratch. The latter is a comparatively modern invention, and has in its turn been superseded by the use of a little steel wheel with a sharp edge.

Pliny's story.

Pliny gives a story of the invention of glass which, if false, is still so picturesque that I cannot resist quoting it here.

A certain merchant-ship touched on the coast of Syria, and the crew landed near the mouth of the river Belus, on a beach of fine white sand which, Pliny says, was still in his day of great repute for glass-making. The ship's cargo consisted of natron,—a natural alkaline crystal which was much used in ancient times for washing,[1]—and the crew having lighted a fire on the sand used lumps of it from the cargo to prop up their kettle. What was their surprise to find afterwards a stream of molten glass running down from their camp-fire. In this case the natron acted as a flux and enabled the sand to melt in the heat of the camp-fire, which, however, must have been a very large and hot one.

Egyptian glass.

Now, whether this story is true or not, it cannot have been the beginning of more than a local industry, for the art of glass-making was known in Egypt from very early times indeed.

Its earliest use seems to have been in the imitation of precious stones, and perhaps for this reason it seems from the first to have been made in colours as well as in white; but the art of blowing it into vessels was certainly known in the fourth dynasty, and in some of the paintings in the tombs the process is actually represented.

It was not, however, till the first century of the Christian Era that any one seems to have thought of using glass to fill windows. In Egypt naturally the climate made it unnecessary, and even in Italy, where it can be cold enough in winter, civilization had evolved a style of architecture independent of glass.

Roman windows.

Nevertheless it was introduced in Rome under the first emperors. Caligula had his palace windows glazed, and Seneca mentions it as one of the luxuries which had been introduced into life in his time, but which did not really add to a philosopher's happiness. Its introduction was, however, very gradual, and even two centuries later its use was still quoted as evidence of excessive luxuriousness.

Remains of these Roman windows have been found at Pompeii and elsewhere. At Pompeii they are in the form of small panes of glass held, in one case in a wooden, and in another in a bronze lattice.[2] It must be remembered that large panes were not available. Another method seems to have been to set panes of glass directly into small openings in stone-work.

When coloured glass was first used in windows we have no evidence to enable us to say. As, however, the manufacture of coloured glass was already a flourishing art it cannot have been long before the idea came of using it to decorate windows.

St. Sophia.

Whether the windows of St. Sophia at Constantinople originally had colour in them or not, is not quite certain. That they were glazed we know, from the description of the church by Paul the Silentiary, an officer of Justinian's court, but his language about them is tantalizingly vague. From his enthusiasm at the effect of the sunlight through them I am inclined to suspect that they were coloured, though he does not definitely say so. Of this glass, which seems to have been fixed in small rectangular openings in a slab of alabaster, nothing, I believe, remains; but similar work—coloured—is to be seen in other mosques, the only difference being that the openings in the slab are formed into patterns and kept very small. (I have already mentioned the necessity, when dealing with clear coloured glass, of keeping the pieces small and contrasting them with plenty of solid dark.)

Mahom­medan windows.

This was as far as stained glass in the East ever got. The Mahommedan conquerors seem to have taken the art as they found it, and continued it down without much change almost to modern times. Their religion debarred them from any attempt to represent living forms, so that the art as it stood sufficed for the needs of their architecture. Visitors to Leighton House may see some of these pierced and glazed lattices from Damascus, and very beautiful they are. In them the pieces are not much larger than a penny, and are set in holes cut in plaster slabs, bevelled on the inside, the glass being set at the outer edge of the hole. The glass is not really of very good quality, but treated in this way even thin poor glass looks rich and jewel-like.

Glass in the West.

What course the glazier's art first followed in the West it is impossible to say, for nothing of it remains earlier than the eleventh century, if as early. Nevertheless, in spite of repeated barbarian invasions, it seems never to have quite died out.

The Church, the refuge of the arts and civilization in the general debacle, sheltered it, and from being the luxury of the Roman millionaire it became the ornament of the house of God. From time to time we get allusions to glazed windows, but never a description that can throw much light on their construction or design. Enough is said, however, to show that coloured glass was sometimes used. For instance, we read that St. Gregory of Tours placed coloured windows in the Church of St. Martin in that city in the sixth century.

One or two facts, however, lead me to think that whereas, in the East, glass was set in stone or plaster, in the West it was usually set in metal. At Pompeii, as we have seen, panes of glass are set in a bronze lattice and fixed with nuts and screws. As colour was introduced it is probable that from the necessity, already spoken of, of keeping the pieces small, several bits would be joined together with lead to fill one opening of the rigid lattice, and so patterns could be formed. Leo of Ostia says his predecessor, the Abbot Desiderius, filled the windows of the Chapter-House at Monte Cassino in the eleventh century with coloured glass, "glazed with lead and fixed with iron"; and certain it is that the earliest existing windows consist of a large rigid lattice of massive rebated iron bars, in which leaded panels have been placed separately, and held there by light cross-bars passed through staples and keyed with wedges.

If this conjecture is correct, we may assume that the art of the glazier had for some time been perfected, and had progressed as far as was possible for it unaided, when its union, probably in the tenth century, with that of the enameller gave birth to the art of "stained-and-painted" glass—that is, stained glass as we know it.

The opaque enamel.

Without the use of enamel the glazier's craft must always have been strictly limited to patterns in glass and lead, or, as we now call it, "plain glazing." What was needed to convert it into the art as we know it was the addition of painting in the black or brown monochrome enamel described in the first chapter.

Only one who has worked in glass, and seen his work grow from a map-like combination of white and coloured glass to the finished glass painting, knows the power the enamel gives him of controlling, softening, and enriching his effects of colour. The power it gives of suggesting form is only one, and not the most important, of its functions, and it was as vital to the work of the twelfth and thirteenth as of the fifteenth century. With its introduction the glorious windows of the Middle Ages became possible.

Exactly when and where the application of the enameller's craft to glass windows first took place it is impossible to say with certainty; but there is some reason to suppose that it was in France, and not earlier than the tenth century.

Venetian enamellers.

Enamel—the art of painting on metal with an easily fusible glass ground to powder, which is then fused on to its groundwork in a furnace—was of ancient invention, and had been carried to a high state of perfection in Constantinople in the eighth and following centuries. Thence by way of Venice it had come to France, where a colony of Venetian craftsmen had established itself before the end of the tenth century.

Monk­wearmouth.

France was already famous for its glaziers: for instance, when in A.D. 680 the Abbot, Benedict Biscop, glazed the windows of the monastery at Monkwearmouth, we read in Bede that "he sent messengers to Gaul to fetch makers of glass (or rather artificers) till then unknown in Britain.... They came, and not only finished the work required, but taught the English nation their handicraft"; and it is probable that the French glaziers, chafing under the limitations of their art, called in the aid of the Venetian enamellers. It is noteworthy that no attempt seems to have been made to use transparent coloured enamel on glass. That mistake was reserved for the decadence of the art seven hundred years later. Perhaps experiment convinced them that enamel colour could never hope to rival the depth and richness of coloured glass, and the glazier would realize that what he wanted of the enameller was not colour but black, to modify and enrich the colour which his glass already gave him in full measure. In this book, therefore, the word "enamel," when used in connection with glass, must be understood to refer, unless coloured enamel is specifically mentioned, to this brown opaque enamel or "paint," as glass-workers call it.

Cloisonné.

But the enameller's art had another influence on that of stained glass. A form of enamelling developed at Constantinople and practised at Limoges was that known as "cloisonné." In this, narrow strips of metal are soldered edgeways to the groundwork and the spaces between are filled with differently coloured enamel, the different colours being thus separated by strips of metal.

When the enameller's attention was first turned to glasswork, in which different coloured pieces of glass were separated by strips of lead, he must have been struck with the similarity of the two arts, and have perceived that the style of design already developed in enamel could be applied with little change to glasswork.

This probably explains not only the apparently sudden birth of the art fully formed, but the strongly Byzantine character of the design in the earliest work, the enameller's art having been brought, as we have seen, from Constantinople by way of Venice.[3]

What, then, is the oldest "stained-and-painted" glass in existence? At Brabourne in Kent there is a small window, of which a coloured tracing may be seen in South Kensington Museum, which may belong to the eleventh century. It consists of a simple pattern of white glass and leading, with small pieces of colour inserted at intervals. Some of these latter, however, have been formed into rosettes of simple design by means of opaque enamel, which is the only painting in the window at all. Whatever the actual date of the window, I think it is not unlikely that it shows the manner in which enamel painting and glazing were first combined.