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Examination of Goldsmith Techniques and Potential Damage of the Coronation Jewels

Andrej Šumbera

The examination of the Czech coronation jewels in 1998 and 2003 focused on specifying the used goldsmith techniques and later modifications and on determining potential damage of the coronation jewels. We used optical microscopes with cameras and digital cameras as well as non-destructive element analyses such as the x-ray fluorescent analysis (RFA) and energy dispersion analysis (EDA). The St. Wenceslas Crown and the royal orb and sceptre were examined in 1998 and the Coronation Cross in 2003.

The use of a modern microscope with a camera greatly helped in obtaining new information about used goldsmith techniques and stone cutting methods. The examination and documentation from the fall of 1998 e.g. helped to determine some techniques and their differences. The documentation also revealed the beauty of many details that are impossible to see with the naked eye. The use of a microscope in determining the method of engraving the sapphire cross of the St. Wenceslas Crown brought the most remarkable results: close-up photographs made it possible to examine the technique of engraving of this hard precious stone (picture 1, picture 2, picture 3). A microscopic view of the burnished gold surface (picture 1, picture 2, picture 3) where we can see marks left by a burnishing device is also interesting. Based on how the burnished surface was filled, we can see e.g. how the crown was created. The pictures of the inner world of the precious stones (picture 1, picture 2, picture 3, picture 4, picture 5, picture 6) are visually very rewarding. The joining of the St. Wenceslas Crown by rivets, cotter pins (picture 1, picture 2, picture 3) and other elements was also examined in detail. The photographs show re-riveting due to a new composition of the crown toward the end of Charles IV’s life.

The examination of enchasing on the royal sceptre and orb is very interesting (picture 1, picture 2, picture 3, picture 4). Both these goldsmith masterpieces were probably made in the same workshop. Under the microscope, we can see every stroke of fine enchasing tools of different sizes that beautifully created especially the scenes on both hemispheres of the orb. The delicate details of the enameling technique used on the orb and sceptre show that both these coronation jewels are prominent Renaissance goldsmith masterpieces comparable e.g. with the crown of Emperor Rudolf II from 1602 or the imperial orb from the treasury in Vienna, which is ten years younger.

The examination of the Coronation Cross in 2003 was also exciting. During repairs that were to improve the overall statics of the cross and the cohesion of components, we were able to take very detailed photographs. Out of 700 digital photographs, the most interesting are the close-ups of beautiful engravings on the precious stones – cameos (picture 1, picture 2, picture 3, picture 4, picture 5). The photographs of the inside of the cross and the relics that will stay locked in their compartments for many long decades are very unique. We could not resist taking photographs documenting the aesthetic qualities (picture 1, picture 2, picture 3) and beautiful precious stones of this ingeniously created cross, either.

When examining the Coronation Cross, we also used non-destructive analyses to determine the gold title (picture 1, picture 2) on some parts of the cross and the composition of other present alloys. The obtained data will be assessed later on.

Goldsmith Techniques Used on the St. Wenceslas Crown

When describing goldsmith techniques used on this prominent and unique monument, we must mention the overall artistic design and how the concept of the crown was created. What was the idea of Charles IV, a young man just getting ready to take the royal road, about the shape and symbolism of the crown? Which scholars formulated the aesthetic, political and liturgical requirements? We will not get a straight answer but let’s try to figure it out, knowing however that there will still be many question marks. It will help us to understand the goldsmith work of the crown.

Visual readability, the impression of stateliness and rareness

In creating the most prominent symbol of his kingdom, Charles IV used his knowledge of many royal crowns and coronation rites since he had visited many European royal residences. These visits surely gave him knowledge in forming the concept of the St. Wenceslas Crown. Its extraordinary design is based on the idea that during coronations, the concept and symbol of the crown can be best conveyed through a simple yet visually strong shape. And this is not all. This symbol was to be also used on seals, coins, illustrations or statues where stylization is necessary; nowadays we would say a successful symbol – logo. We can feel the timeless success of Charles IV’s intent to this day: the symbol of the crown cannot be mistaken and we cannot miss it even on today’s many graphical products.

Let’s go back to the visual effect of the crown at a short and long distance – it is a logical requirement since, during coronation rites, most participants were watching from a long distance. In this case, the crown can be considered a well-made statue making use of distinct and simple shapes, an entirety with a clear concept and design. Yet, the monumental and greatly simple design creates compelling effects that are achieved by the ingenious proportions of the crown. The precious stones are set in such a way that they seem to be suspended in the space above the gold surface (picture 1, picture 2, picture 3, picture 4) that reflects the color of the precious stones and the reflection of the sockets; the overall effect is accentuated by reflections of light (picture 1, picture 2, picture 3). Potential movement of the crown or lights in the cathedral only enhances the overall impression and creates a compelling visual show. In addition to the ingenious optics, we must keep in mind the necessary prestige aspect of the crown – the requirement to use the best materials that need to be adequately displayed. Besides gold, there are especially very rare precious stones: their polished large surfaces are visually spectacular (picture 1, picture 2), beautifully enhance their colors and make them gleam. The right shape of the sockets and their reflection on the gold surface of the crown create a halo around the precious stones.

The composition of the precious stones

The lilies growing out of the headband are set with five precious stones, except for the front lily that has only four stones because of the large central rubellite. The opposite lilies always have the same color of precious stones; red on the front side and the back side and blue on the right side and the left side. The crown thus gives a distinct and balanced impression, which could not be achieved by any less thought-out color composition. The precious stones on the headband alternate in color and size – large blue sapphires take turns with smaller red stones. The following fact proves how well the composition was thought out. The precious stones on the front side of the headband alternate is such a way that a large stone is in the middle and smaller stones are on each side; if it were the other way around, there would be two large dark blue sapphires “duplicating”, in fact, the king’s eyes. The large sapphire in the middle of the headband looks like God’s Eye.

On the back side of the crown, there is another interesting thing: the bottom row is set with two groups of five smaller red stones that, thanks to their concentration in one place, become equivalents in the composition rhythm. It is probable that some of the smaller stones came from the original design of the crown.

The symbolic meaning definitely played the most important role in arranging the precious stones on the St. Wenceslas Crown. The crown is not only a personal royal crown; it is a reliquary object with a thorn from Christ’s crown. It was consecrated to St. Wenceslas, the Czech saint and the patron of the land, and was to be permanently placed on the head of his gold bust to be removed for a new king’s coronation and during big religious feasts only.

This information about the composition and optical aspects of the crown is important for the following description of used goldsmith techniques since it explains why fine ornaments were left out. It is necessary to point out that the decorative techniques such as enamel, enchasing, filigree, graining or engraving, were not used on purpose since they would disturb the grand concept of the St. Wenceslas Crown.

Used Goldsmith Techniques

Structure and materials

The crown is made of a rather thin gold plate – the objective certainly was to make the crown light, and the structure and individual goldsmith techniques were adapted to this requirement. The headband parts are cut out of a plate that is only 0.6 to 0.8 mm thick (measured at six different places); if the plate were 1 mm thick, the total weight of the crown would be about 600g more and the king would have to carry a three-kilogram weight on his head! The thin plate is reinforced with the right structure and especially with the edge that has an oblate wire brazed on. It is a traditional goldsmith method of how to visually accentuate and reinforce a thin edge.

Joints

From a technical point of view, the entire St. Wenceslas Crown is an ingenious set of blocks – individual parts are joined with hinges and can be easily dismantled after the cotter pins are removed. The crown consists of four basic parts: front, back, right and left. The joints are between the lilies and go through the entire height of the headband. The cross-forming arches are two gold bands that are attached to the headband by hinges at the foot of the back of each lily. The last separate part of the crown is at the top of the cross-forming arches; it is a cross held in place with a cotter pin. The crown is a perfect example of Gothic goldsmith work, for which ingenious joints were typical and became a part of the entire artistic design and a decoration.

Sockets

The most compelling goldsmith details creating the visual effect of the St. Wenceslas Crown are the sockets with the precious stones. Chalice-like settings grow out of the pedestals in the form of a low pyramid with mostly square-shaped bases; the precious stones are thus splendidly raised above the surface of the headband (picture 1, picture 2, picture 3) that however does not lose its splendor because the precious stones seem to float above it. The perimeter of all the precious stones usually overlaps the edge of the socket setting, which shows off the volume and surface of the precious stones. The shape, height and edge of each setting or the size of each base is different and the tailored sockets nicely complement the layout of the precious stones – they compensate for the different height or even size of the precious stones. Sockets with a double outer edge are to make a smaller stone optically bigger and to raise it so that it would not be overshadowed by its more distinct neighbors. The setting of the large rubellite on the front side is very unique: the stone is held in place only by three long prongs allowing the polished natural stone of an irregular shape to stand out from the sides as well.

The front side has another interesting thing: parts of the square-shaped pedestals of the sockets in the bottom row on the headband were cut off to lower the sockets. It was done for a very practical reason: originally, the precious stones were protruding too much, getting in the king’s field of vision, which must have been unpleasant during ceremonies.

The sockets are made of a thin gold plate that is even thinner than the plate of the lilies; it is probably 0.5 to 0.6 mm thick (it cannot be measured exactly). The prongs (picture 1, picture 2) that hold the precious stones in place grow out of the side of the sockets. In the mentioned charming effect of the halo around the stones, the sockets make reflections on the shining surface of the crown.

Cross-forming arches

The two arches that connect the opposite lilies crosswise are made of two gold bands with delicate goldsmith rectangles (8) and squares (4). Right away, they look different from the rest of the crown, the concept of which is majestically severe and monumental. The cross-forming arches are more decorated, there is e.g. graining on the edges. The arches were originally a part of the belt made in Paris that Blanche of Valois, Charles IV’s first wife, had received as a wedding gift. The rectangles are set with a bigger stone held in place with prongs and surrounded with a couple of smaller stones in a fixed setting. The color combination is again balanced: if the central stone is red (spinel), it is surrounded with green stones (emeralds) and vice versa. The squares adorned with a precious stone are in the middle and surrounded with pearls. The arches are attached to the lilies with hinges.

How the gold surface of the crown was burnished

Reflections of the gold surface are an important part of the overall impression. The finish of the surface was done by a steel burnisher; it is a traditional technique where the surface is burnished by pressing and moving the burnisher – the surface of the hard burnisher is imprinted onto the burnished surface, which makes the pores in the burnished surface close and creates a high shine. This type of finish is also good in another respect: the marks of the burnisher leave a typical slightly grainy shine that cannot be achieved by any other burnishing technique.

Goldsmith work

Let’s try to visit a medieval goldsmith workshop where the St. Wenceslas Crown was made. It is believed that back then goldsmiths lived in the Golden Lane at the Prague Castle. As we have already suggested, the concept and composition design of the crown preceded concrete goldsmith work. The concept of the work of such great importance had to be created by a close circle of people around Charles IV, however, the selection of precious stones had to be consulted with the goldsmith, who thus became a party in making the crown and decided how to attach precious stones. The selected precious stones and pearls were then most likely set on a crown maquette, and sockets were made after the composition and setting were specified. Each socket was tailored to the shape of the precious stone, and its height and form was made to complete the overall composition. We can assume that the sockets with the precious stones were tested one more time on the maquette to make the composition perfect. After that, the lilies of the crown were made and the sockets with the precious stones were riveted to the parts of the crown. Finally, the four lilies were connected with the cross-forming arches that were then topped with the cross. All these parts can be easily dismantled.

Cutting of the precious stones

The St. Wenceslas Crown has beautiful and extremely invaluable precious stones. They were found in different fields and at different times and most of them were used before. For example, the drilled-through sapphires were found in Ceylon (Sri Lanka) and could have been used as jewelry for many thousands of years; they were originally strung. Notice the shape of most of the stones: it is obvious that the stone-cutter tried to preserve as much volume as possible and kept the oval shape of the stone, doing only the most essential cutting.

From a historical point of view, it would be interesting to know the history of the precious stones, to know which goldsmith masterpieces they used to adorn before. While gold was often melted and re-used for other jewels, precious stones go through history usually unchanged because any change would make them lose their biggest value – volume. This is why we do not think that these precious stones were cut in Prague workshops – they were only repolished or slightly changed there. An exception are the precious stones with a facet cut, which was a novelty that did not become popular until after 1370; these precious stones could have been cut in a Prague workshop. The sapphire cross is a Byzantine work. It was originally a pendant; it has dents on the front side made probably by other precious stones on the same string. The back side of the cross is burnished using a straight grindstone, which is in contrast with the front side. It was probably burnished later on in Prague before it was placed on the St. Wenceslas Crown. A residue of the grindstone putty that we can see on the close-up photograph is interesting.

The Most Interesting Results of the Examination of the Crown

Modification of the crown

The crown was changed toward the end of Charles IV’s life after he obtained more precious stones and decided to slightly modify the concept of the crown. The belief that the crown was changed by gradually switching the precious stones around must be false since the final excellent color and composition balance could have been achieved only by removing and repositioning all the precious stones. Thanks to the fact that the sockets are riveted in, it was rather easy to change the composition and no torch brazing was required, which would have ruined the polish and the crown would have had to be reburnished and the precious stones removed from their sockets to prevent their damage by fire. Only the front part of the headband had to be repaired by fire since its composition of the precious stones was changed so much that it affected the surface; the holes were repaired by brazing two new gold plates onto the back side so that new sockets could be riveted in well. On the front part of the crown we can also see a different type of burnishing: while the other parts show continuous long marks of the original steel burnishing, the front part shows burnishing marks going in different directions. This information proves that the front part was repaired.

The sapphire cross

Inside the gold cross there is a sapphire cross with the Crucifixion. This cameo is believed to be a Byzantine work, which is proven by the engraving technique (picture 1, picture 2, picture 3). Based on the photographs taken by a microscope, we can now determine how the engraving was made. It was made by the traditional gem engraving technique where pieces of the precious stone were removed and the relief was created by a rotating abrasive disk made of copper. The disk was placed on a shaft usually driven by a bow and an abrasive was powdered underneath; in the case of hard sapphires, it was a diamond powder. The fact, which is often cited by authors, that it took an engraver his whole life to engrave a relief in a sapphire with a diamond is totally misleading and so is the information that engravers did not use a magnifying glass; this only shows the gross ignorance of such authors.

A note on a relic

Some sources talking about the St. Wenceslas Crown mention that there is a tiny part of the thorn from Christ’s cross either in the drilled loop of the sapphire cross or in the hollow of the gold cross around it. However, upon examination of all sides of the cross, no entrance to the hollow was discovered that would confirm this assumption. It is more likely that the relic is in the drilled loop of the sapphire cross that used to be a pendant. The close-up microscopic photograph however does not show any such relic; the shadow in the upper part of the cross is caused by some dirt on the wall of the hollow. Nevertheless, the relic could have been placed in the hollow of the drill.

A note on the sapphire

Old articles of inventory mention a sapphire that originally formed the base of the cross. If such a sapphire existed, it had to be drilled through and a pin attaching the cross to the crown had to go through it. This rather complicated method could have broken the sapphire in half – even the slightest impact would have bent the pin and the resulting pressure would have broken the sapphire. Today’s setting of the cross is not the best; if we look at the entire line of the crown, we can see that the cross is somewhat lower. When looking from the level of the pearls on the top of the lilies, the sapphire cross is slightly covered (drowned in) and should be at least 10 mm higher, which could have been the height of the missing sapphire.

Goldsmith adornment on the cross-forming arches

The finding of dr. K. Otavský that the adornment on the cross-forming arches came from the belt of Blanche of Valois, Charles IV’s first wife, that she had received as a wedding gift can be supported by other arguments as well. The goldsmith work is different (more decorative) and the analyses of the used gold show a different alloy than that of the actual crown. The fact that it was a belt is clear from the joining of the parts of the squared composition by a flexible hinge system that can be used only for belts and not e.g. for pendants. Another argument in support of this opinion is that the length of the belt corresponds with a young girl’s tiny waist. If we take into consideration the fact that eight rectangles placed on the crown originally alternated with smaller squares and that the belt had to have a buckle, the total length of the belt would be about 60 cm; when Blanche of Valois got married, she was only seven years old.

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