By way of introduction to the block of studies on the technique of the Theodori's panel paintings it is necessary to draw attention to the open nature of a number of the problems. The extensive restoration work which has been under way in the Chapel of the Holy Rood since 1979 is gradually expanding the state of knowledge as to details which have not yet been studied. This unique set of pictures, plastic decorations and incrustations of precious stones, ascribed in general to the authorship of Theodoricus, is beginning, in the course of the restoration, to be separated more clearly into parts done by several different hands, i. e. several artists, led categorically by the programe set by the leading Master, as indeed was the idea which Antonín Friedl attempted to study years ago. Inter alia the question has arisen of the originality of the pastiglia, the differentiation of the periods of origin of individual alternations, and the problem of the date of the actual completion of the decoration in the Chapel. We are trying today to reconstruct in great detail the actual process of the technical realisation, influenced also by changes in the programme of decoration.

As an introduction to the problems we should like to refer to the basic works by Bohuslav Slánský and Mojmír Hamsík, which are quoted in the bibliography of the first issue of this yearbook, and also to the art historical works of A. Matějček, J. Pěšina, A. Friedl and K. Stejskal, as well as numerous other pieces of literature quoted in the individual articles.

The attentive reader will notice certain differences of opinion between the authors imparting their findings here, conditioned, inter alia, by what part of the material they came into closer contact with. The fears connected with the premature publication of findings which differ are, in the opinion of the editors, unfounded as the differences in opinion can only be beneficial to the exchange of standpoints on academic ground. It rather goes to show that our field is working its way out of the period of isolated research by individuals and into exact dialogue and mutual verification. The precision instruments which historical art technology now has at its disposal consist not only of laboratory analyses, but also in the detailed study of stratigraphy, in the interconnection of historical sources. This precise comparison of partial findings is still before us.

The Editors (J.D.)


Relief decoration, called pastiglia pastillaye, yesería, relieve en stucco, applique relief, plasterreliefis a form of sculpture set in the painting or rather a proof of a special conception of synthesis of the two. This has been a source of interest to a number of researchers, and it has been studied from various points of view since the seventies, always in connection with Byzantine painting 1. M. Frinta has convincingly explained the origin of this plaster relief in the eastern Mediterranean region in a series of works 2. This author attributed the spread of the technique of relief decorations to the Crusades. The »Crusaders art« sank roots in many places along the routes of the Crusades, especially in Mediterranean ports and spread asfar as Spain where the technique of pastiglia appeared in Catalonia from the 13th century. Another important centre was Naples from where, it would seem, the popularity of relief decorations spread further north, to Pisa, Florence and Siena. In the 14th century it reached the Netherlands, the Rhineland and Westphalia. We can find examples of pastiglia in England, too, already from the end of the 13th century, and English scholars have often linked that to strong Italian influences 3.

It is not clear why this popularity reached such remote regions, continued for centuries and was not necessarily bound to any style 4. For Bohemian Gothic painting the problem is interesting particularly in relation to Master Theodoric, and his circle. This paper sets out to recapitulate the existing results of the study of pastiglia in European painting and to characterize this technique on 14th century panel and mural painting in our country.

Master Theodoric, Adoration of the Magi. Detail, painting in the Holy Rood Chapel at Karlštejn Castle, before 1367. Pastiglia of the silicious material.

Proofs of the substance of pastiglia as imitation of metal decorations on the oldest icons were gathered by M. Frinta in his work on Cypriot icons. (He drew attention to the significance of ornamental motives on those metal decorations for the flat relief of the gilded background)5. The author discovered that apliqué relief does not exist in the very centre of Byzantine culture, in Byzantium, only in the marginal regions such as Cyprus and the Sinai Peninsula. Its popularity continued longest on Cyprus, for five centuries beginning in the 13th century. It seems that in the eastern conception that is not known in the western type of plasticity the pastiglia take the form of low relief with added painting, which is also known from the oldest examples of Balkan icons. In Western Europe the appearance varied from the middle of the 13th to the middle of the 15th century when the eastern reminiscences vanished.

The technique and the material composition differs from region to region and seem to have depended on the availability of suitable material. Each region drew on local supplies: customary for northern Europe is common white chalk or grey mountain chalk, for the southern region, gypsum (gesso). The technique is simillar as can be deduced from the description in Cennino Cennini's Book on Art, where a total of eight chapters is devoted to pastiglia. The author of the manuscript describes three basically differing techniques, the application of relief with a brush, the impression of a stone mould into tin-plate and finally the casting of relief from a mould. There is a broad selection of material: for the application of relief with a brush to the panel picture they used fine gesso, on the wall, lime with sand or a mixture of flour and varnish, occasionally wax and resin 6. For both purposes relief was suitable that was imprinted from a stone to the tin-plate which was then filled with gesso and attached with ship pitch. Gilding was carried out on an oil base. As comparative material the most interesting for us is the description of the preparation of the relief cast of gesso for application on a panel picture. The bonding agent is »stronger» glue, the mould is made of clay, insulated with non-solidifying oil used for lighting; the attachment was carried out with fine gesso identical with the ground for painting.

The Italian manner of applying fine runny plaster with a brush has been proved by detailed analyses carried out in the laboratory of the London National Gallery 7. Rich comparative material is provided by Catalonian panel painting from the 13th to 15th century. The technique of applying plastic ornament (relieves de estuco) with a brush to black linear preparatory drawing is shown on the altar front in Neo-Byzantine style from the early 13th century of Chio at Huesca. In the mountain regions of the Pyrenees diocese of Lérida a characteristic simplified technique of gold glazing (corladura) has survived on metallic, most probably tinny foil that covers the relief surface 8.

St Jerome. Detail of the wall painting »Maesta« by Simone Martini in Siena plaster of gypsum (»gesso«) and real parchment.

The technique of casting prefabricated pastiglia from chalk bonded with glue can be shown on the St Clare altar in Cologne cathedral in the Rhineland; this appears on the inner side of the movable wings where the painting is carried out on canvas. The siting of the individual plastic motives is pre-drawn with a linear network engraved in the chalk ground. Remnants of metal foil have been found on the surface of the pastiglia, probably used as insulating layer in casting. The gilding is carried out on a oil layer coloured with red lead. The altar dates from the middle of the 14th century and is a combination of painting and sculpture. Christa Schulz Senger 9 is of the opinon that the impression of the relief decorations is strikingly similar to the gilded metal reliquiaries in the same cathedral.

The connection of pastiglia and the original metal decorations is proved at Karlštejn Castle by the existence of pewter relief ornaments in the back ground of the picture of St Simon in the Holy Rood Chapel 10, whose position is determined by the engraved and punched squares on the gilded background with which they originally blended, for their surface was likewise gilded. According to restorer Jan Pasálek, there are remnants of metal relief ornaments also on the mural paintings in the same chapel.

Macro-photos of plastic elements on Theodoric's paintings. Above tinny applique on the picture of St Simon, below siliceous pastiglio of the sword on the picture of St Catherine.


The Holy Rood Chapel at Karlštejn Castle before Mocker's renovation (from Neuwirth's publication, 1896, PI. XXIX)

A number of authors have mentioned the relationship between pastiglia and goldsmith's art. Vlasta Dvořáková, speaking of the Hungarian and St Wenceslas Chapels in the cathedral at Aachen, which arose on impetus of Charles IV and were decorated with panel altarpieces, says that the common feature of these reliquiary icons is a relief background, relief ornaments on the garments, the application of precious stones and partly gilded metal plate set in the area of the painting« so that... »they came close in execution of goldsmith's work of the Italian-Byzantine character 11

Often stress is laid on the symbolical meaning of gold and precious stones as supra-natur al matter representing a higher, imaginary world. The same meaning was clearly achieved by the pastiglia with their gold foil cover. Karlštejn Castle is an example of the combination of precious metal in the form of crosses, buckles, and perhaps even crowns, nimbuses and rays and the technique of gilded pastiglia used on the background of the panel pictures on the linking panelling, the edges of precious and semi-precious stones, on the mural paintings, 12 the ceiling and on the stone elements of the architecture.

Detailed investigations in the laboratory of the National Gallery in Prague have shown that the composition of the pastiglia on Theodoric's panels in the Holy Rood Chapel is considerably varied 13 The basic types of material are chalk, and silicious clay; there are also combinations with various pig ments. A mixture of pigments alone is rare. These two basic types can be found on the same panel, even alternating according to the kind of ornament on the garments. The pigments used are red and yellow ochre and minium; the bonding agent of the chalk is solely glue while silicious material is bonded with starch and egg-white with an admixture of oil The mixture of pigments alone contains only oil. There is an important finding that the silicious material of the infill is in its detailed composition, i.e. an admixture of yellow and red ochres, black particles and calcite, and in the kinds of bonding agents, comprising starch, egg-white and oil, entirely identical with the lower strata of the ground of the painting. Of the twenty pictures under re-seach seventeen had this composition oftheplastiglia, irregardless of the fact that were on a chalk priming, on silicious layer or direct on the wood. An exception to this was the picture of Apostle Luke where they found a mixture of yellow and red ochres bonded with starch and oil and coagulated chalk with the same pigments and identical bonding agent. Another exception were the metal ornaments on the picture of St Simon and the newly reconstructed chalk pastiglia of St Paul that differs already in external appearance, namely in the sharp outlines of the relief.

These data refer to the decorations of the background; in the composition of the pastiglia inside the area of the painting laboratory tests have shown a predominance of chalk bonded with glue. Silicious material is in the minority, there are exceptional mixtures of pigments (yellow ochre, minium) bonded with oil. All pastiglia on the area of the painting are glued to a layer composed of red and yellow ochres and minium, occasionally with an admixture of lead-tin yellow bonded with oil and rosin. In all cases this is a type of cast, prefabricated ornament made in series, differing in number according to the size of the motive and amounting to up to nine pieces. The black amorphic matter on the surface of several paltiglia has been identified in the laboratory as metamorphozed tin, which indicates that metal foil was used as insulating material.

Master Theodoric, St Helena
(Holy Rood Chapel at Karlštejn, 1365-67). Photo Čestmír Šila

Since essential restoration work was carried out at Karlštejn Castle in various historical periods, the question of the origin of the plastic decorations has been raised, the more so after the discovery of tiny fragments of gold foil on the edge of the figures; certain restorers in recent times have had romantic ideas about the original appearance of the pictures. In addition, the fact that the chalk priming layer is cut around the outline of the painting in about a half of the pictures in the Holy Rood Chapel has led to a number of speculations as has the discovery that the pastiglia and their gilding in some cases cover the edge of the painting.

On the question who made these gilded decorations interesting ideas have been put forward by Mojmír Frinta 14 suggesting an equal evaluation of, the painting and the ornamental gilding. Two signatures have been found on the »Monteoliveto« altar, one referring to the painting, the other the gold ornaments. A painted cabinet with rich pastiglia is also signed twice; it derives from the town hall in Siena. A further proof of collaboration between the painter and the artist who made the apliqué relief is, according to M. Frinta, the »Maesta« of Simone Martini, again in the Siena Palazzo Pubblico and his Madonna with Saints in the lower church at Assissi. The application of plastic adornment on the mural painting of the Maesta prchaly arose after a certain lapse of time, to judge by archive records of expenditure and here, too, the reliefs cover the painting in places. At Karlštejn Castle, too, one should assume broad collaboration between specialized masters and their assistants. The demanding nature of the work required a division of labour where not always the binding method of material composition was adhered to, as shown elsewhere 10.

Mojmír Hamsík, AHVT A 027 (T.G.)

1 D. T. Rice, Cypriot Icons with Plaster Relief Backgrounds, Jahrbuch der österreichischen Byzantinistik, XXI, Vienna 1972. A. Grabar, Les revetements en or et en argent des icones by/antines du moyen age, Venice 1975.

2 M. Frinta, Relief Imitation of Metallic Sheathing of Byzantine Icons as an Indicator of East-West Influences, The High Middle Ages, Acta, Vol. VII, 1980.
M. Frinta, Raised Gilded Adornment of the Cypriot Icons, and the Occurence of the Technique in the West, Gesta, International Center of Medieval Art, Vo.XX/2, 1981.
M. Frinta, Relief Decoration in Gilded Pastiglia on the Cypriot Icons and its Propagation in the West, Acta of the Second Congress of Cypriot Studies, Nicosia 1986.

3 Amanda Simpson, English Art during the Second Half of the 14th Century, Resultatband zur Ausstellung Die Parler und der schöne Stil 1350-1400, s. 137-159, Köln 1980. P. C. Van Geersdaele, L. J. Goldsworthy, The Structure, Pigments and Medium of some Samples from the St. Stephen's Chapel Wallpaintings in the British Museum, The Conservator, Vol. 2, 1978, s. 9-12. The St Stephen 's Chapel at Westminster, dated to the middle of the 14th century, was adorned with rich relief decorations, as shown by frag ments of the story of Job now in the British Museum. Analyses of the material composition of the pastiglia have brought the surprising discovery that it is a mixture of minium and lead white bonded with oil and an admixture of egg-yoik (Van Geersdae..., op. cit. – see above)

4 An example of the relatively late use of plastic decorations in the form of vine tendrils are the panels with the Deposition in the Tomb in the museum at Ipswich, dated to the first half of the 15th century and following the West European type in style.

5 M. Frinta, The Decoration of the Gilded Surfaces in Panel Painting around 1300, Europäische Kunst um 1300, CIHA; Wien 1983, s. 69-75.

6 A related technique of relief decorations made of wax and resin is found e.g. in 15th century Spanish panel painting particularly on statuary of the Hispano-Flemish circle, Alsace and the Rhineland (M. Frinta, The Use of Wax... see above). In the author's view the decorations were prepared with the aid of stamping dies on a  thin layer of wax with an admixture of resin, then cut apart and applied to the surface of the panel or the statue. The advantage was considerable elasticity that facilitated the shaping of the complex Late Gothic folds. A similar technique of pastiglia of red wax, which contains minium, is described by Anne Brodrick and Josephine Darrah in their work on the tomb statuary of the Duke of Arundel William Fitzalan and his wife: Church Monuments, Vol. 1, 1986, pp. 65-94. The authors are of the opinion that the relief adornment was cast in a metal mould. Tin plate has survived on the surface of the pastiglia, and this was covered with oil gilding. The tin might have served as insulating layer.

7 Art in the Making, Italian Painting before 1400. D. Bomford, J. Dunkerton, D. Gordon, A. Roy, Jo Kirby. National Gallery, London 1989-90. The authors assume that the pastiglia on Jacopo di Clone's Crucifixion were composed of a mixture of lead white and gesso.

8 Miguel A. Alarcia, Museo de arte de Cataluna, s. 3-11.

9 Christa Schulze-Senger, Der Claren-Altar im Dom zu Köln, Kölner Domblatt 1978, s. 23-36. On the Relief Adornment in the Klarenaltar and Other Paintings in Cologne ve sborníku Die Kölner Maler von 1300-1430, Köln 1976, s. 131-139.

10 M. Hamsik, Theodorik a dílna – addenda k technice malby, Umění XXXIV, 1986, s. 64-68.

11 V. Dvořáková, Karlštejn a dvorské malířství doby Karla IV, in: Dějiny českého výtvarného umění 1/1, s. 320, ČSAV 1984.

12 M. Hamsík, J. Tomek, The typical material of the pastiglia on Theodoric 's panels, i.e. silicious clay with an admixture of yellow and red ochres bonded with starch, egg-yolk and oil, is entirely identical with the material of the pastiglia of the mural paintings in the Holy Rood Chapel at Karlštejn Castle and in St Vitus'Cathedral in Prague.

13 The Puzzling Raised Decoration in the Paintings by Master Theodoric, Simiolus 8, 1976, s. 271-300.

14 M. Frinta, Stamped Halos in the 'Maesta' of Simone Martini, Atti del convegno, 1988, s. 139-145. The material of the relief decorations of the maesta is discussed by E. Borsook – in the author's view it is gypsum. According to verbal information of restorer Camilla Tarozzi of Bologna there simultaneously existed in the Italian technique of the first half of the 14th century wax bon děd with Bologna chalk as material for pastiglia, e.g. in the mural painting of Vitale da Bologna.