This paper discusses a methodology that involves the use of x‐ray fluorescence (XRF), high energy... more This paper discusses a methodology that involves the use of x‐ray fluorescence (XRF), high energy particle induced x‐ray emission (HE‐PIXE) and particle induced γ‐ray emission (HE‐PIGE) spectroscopies for the study of historic denars with the aim of describing the advantages and limitations of each technique as well as arriving at an archaeometric interpretation of the compositions. Thirty nine medieval Polish denars minted by Kings Bolesław the Brave and Mieszko II Lambert were analysed for their elemental composition. While XRF is limited to the analysis of the material close to the object´s surface, high energy ion beam analysis was used to obtain information from Cu at a relatively larger depth. The major elements detected were Ag and Cu, while the minor elements were Pb, Au, Bi, and Zn. An evaluation of the results obtained with the different techniques shows that the content of Cu near the surface is different from the bulk composition of the coins. The obtained elemental composition was used to proliferate the understanding of chronological changes in the production of early medieval Polish denars.
Naturwissenschaftliche Informationen, insbesondere die chemische Zusammensetzung der Objekte, kön... more Naturwissenschaftliche Informationen, insbesondere die chemische Zusammensetzung der Objekte, können Hinweise auf die Hintergründe der Objektherstellung liefern, die der alleinigen kunsthistorischen Begutachtung verborgen blieben. Es können nicht nur Fragen nach dem Prozess, Zeitpunkt und Ort der Herstellung beantwortet werden. Die chemische Analyse gibt auch Hinweise auf Ereignisse und Veränderungen, die erst nach der Fertigstellung des Objektes erfolgten. So werden Alterungsphänomene oder historische Überarbeitungen und Restaurierungen aufgedeckt, aber auch Konservierungsstrategien zur Erhaltung der Kunstwerke unterstützt. Durch den technologischen Fortschritt im Bereich der röntgenanalytischen Methoden, die berührungsfrei, ohne Probennahme und ohne Schädigung für das Untersuchungsobjekt arbeiten, erschließen sich dem Analytiker erstmalig Möglichkeiten, auch sehr wertvolle und fragile Objekte zerstörungsfrei zu untersuchen.
French enamellers active in Limoges during the late fifteenth to the early seventeenth century we... more French enamellers active in Limoges during the late fifteenth to the early seventeenth century were noted for their fine painted scenes taken from classical mythology and Christian traditions. The forms made in the Limoges workshops included plaques, plates of various sizes, ewers and ewer stands, salt cellars, candlesticks and footed bowls, all of which were intended to be decorative rather than functional. Instead of the more obvious painted enamel surfaces, this study examines the metalwork of these vessels. The metal, entirely hidden beneath the enamel, is generally of sheet copper. While the study of damaged objects reveals constructional features, X-radiography of unaltered enamels, complemented by examination using a microscope and boroscope, has made it possible to understand the construction of the more complex shapes. The methods used to join the components are quite unlike those seen in sheet metalwork that was not intended for enamelling, and are partly explained by the ...
Non-European dyed materials other than textiles have received comparatively little systematic ana... more Non-European dyed materials other than textiles have received comparatively little systematic analysis, this is particularly true for objects made with dyed porcupine quills. This paper presents a comprehensive study of a group of Athapaskan porcupine quill specimens collected in 1862 which are held within the collections of National Museums Scotland, UK. Due to sampling limitations micro-destructive testing, or non-invasive analysis using PDA-UPLC, Raman Spectroscopy and PIXE were used to characterise the dye sources and metallic mordants. RBS was used to obtain additional information on the depth-profiling of the mordants in the keratin-based quill. The sensitivity of the quill specimens to photo-degradation was evaluated using Micro Fade Testing (MFT). The results from this multi-analytical study will be used to inform future display regimes of this unique collection.
The recovery of the Dacian gold bracelets was the most thrilling archaeological event of the last... more The recovery of the Dacian gold bracelets was the most thrilling archaeological event of the last years in Romania. The artefacts are exhibited in the Historical Treasure section of the National History Museum of Romania, Bucharest, being recovered from the international antique markets through a concerted effort of the Romanian, French, and German authorities. This paper reviews the X-Ray Fluorescence (XRF) analyses carried out on these exquisite artefacts. These measurements followed the visual examination of qualified experts, which concluded that the gold spiralled bracelets showed strong stylistic similarities with the Dacian silver bracelets discovered until that date in archaeological contexts. Since the most likely source-for geographical and historical reasons-for the metal used to manufacture these artefacts was the Transylvanian Apuseni mountains, additional measurements on several fragments of natural Transylvanian gold, both from placers and primary deposits, were performed using Synchrotron Radiation X-ray Fluorescence (SR-XRF) at the BESSY synchrotron, Berlin, and micro Particle Induced X-ray Emission (micro-PIXE) at the AGLAE accelerator, Paris, and at the AN2000 accelerator of LNL, Padova. The conclusion of this study was that the recovered spirals are genuine Dacian artefacts, made by cold hammering, chiselling and punching Transylvanian unrefined gold-gold panned from riverbeds mixed with primary gold, most likely extracted from surface veins. Résumé : La saisie des bracelets en or de Dacie a été un des événements archéologiques les plus remarquables de ces dernières années en Roumanie. Les objets sont exposés dans le Trésor Historique du Musée National d'Histoire de Roumanie, Bucarest, et ont été récupérés du marché international d'antiquités grâce aux efforts concertés des autorités Roumaines, Françaises et Allemandes. Cet article fait le bilan de l'analyse de ces objets exquis, réalisée par fluorescence à rayons X (FX). Ces mesures suivent l'examen visuel par des experts qualifiés qui ont conclu que les bracelets en or à spirales montrent des similitudes stylistiques fortes avec les bracelets en argent de Dacie découverts en contexte archéologique. Comme pour des raisons historiques et géographiques la source la plus probable du métal utilisé pour la fabrication de ces objets se trouve dans les Carpates transylvaniens, des mesures complémentaires ont été réalisées sur différents fragments d'or natif de Transylvanie, provenant tant de placers comme de
... For this reason, and because of the general problem of surface deterioration mentioned above,... more ... For this reason, and because of the general problem of surface deterioration mentioned above, the ... flat plaques or medallions, where on the reverse side no pictorial scene is painted, a so ... in the object caused by the different thermal expansions coefficients of the copper and the ...
To hinder the phenomenon of weathering of ancient stained glass, the present work proposes the ap... more To hinder the phenomenon of weathering of ancient stained glass, the present work proposes the application of sol-gel coatings to the glass surface. Previous investigations [1-6], in fact, show that sol-gel silica coatings do not change the appearance of artistic glasses when deposited on their surface. Moreover, the film thickness is so small (around 200 nm) and its composition and structure so compatible with that of the original glass, that the characteristics of the coating and original glass are not distinguishable. In this work, several recipes used to produce sol-gel coatings have been tested in order to understand their behavior when adopted for covering ancient weathered glass. The coatings are made of sol-gel silica prepared with two different catalysts: H + , Pb 2+ and without catalyst. All the investigated samples show a good adhesion of the coating to the glasses used to simulate the behavior of ancient artefacts. The sol-gel silica coatings have been studied before and after accelerated ageing to test the resistance of the protective coatings to weathering. Another important index to test of the efficiency of the sol-gel coatings for the protection of an ancient glass is the lead ion mobility. In ancient stained glass, in fact, this element is present in the metallic lead network, in the grisaille paintings and constitutes a main component of many glass tesserae. The action of water on this highly mobile ion involves the degradation of the glass itself and the release of the ion in the rain solution. Ageing tests show the efficiency of H + and Pb 2+ catalyzed coatings and the inefficiency of the non-catalyzed sol-gel layers.
The salt [Na.15-crown-5][Ni(mnt) 2 ].H 2 O has been prepared by electrocrystallisation and charac... more The salt [Na.15-crown-5][Ni(mnt) 2 ].H 2 O has been prepared by electrocrystallisation and characterised by X-ray crystallography showing a stacking arrangement of [Ni(mnt) 2 ] À and a slipped stack arrangement of the crown ethers.
Applied Physics A g. padeletti 1,u g.m. ingo 1 a. bouquillon 2 s. pages-camagna 2 m. aucouturier ... more Applied Physics A g. padeletti 1,u g.m. ingo 1 a. bouquillon 2 s. pages-camagna 2 m. aucouturier 2 s. roehrs 2 p. fermo 3
STAR: Science & Technology of Archaeological Research, 2019
Cobalt was commonly used as a colourant in the Egyptian glass industries of the 18th dynasty, dar... more Cobalt was commonly used as a colourant in the Egyptian glass industries of the 18th dynasty, dark blue glass being a regular find at palatial and settlement sites, including Amarna and Malqata. The main source of cobalt ore used during this period has been identified in the Egyptian western desert, around the oases of Kharga and Dakhla. In order to better understand the chaîne opératoire of Late Bronze Age glass production and-working, in particular with regard to cobalt ore, at Amarna, chemical analysis by portable X-Ray fluorescence was carried out in the field. This was done on contextualised archaeological material excavated at the site of Amarna, which cannot be exported from Egypt for analysis. The results of this study demonstrate how cobalt ore was used in the various known workshop sites at Amarna, resulting in a deeper understanding of raw materials use and exchange across this settlement.
Bodies and glazes of tiles from the Ilkhanid period found at the UNESCO World Heritage site of Ta... more Bodies and glazes of tiles from the Ilkhanid period found at the UNESCO World Heritage site of Takht-e Soleyman were studied to identify materials and certain technical characteristics of the architectural ceramics as part of a larger project to establish different productions. In addition, ceramic vessels and technical ceramics excavated at the site were analysed for comparison. µXRF, SEM/EDX, and Raman spectroscopy were used for the material investigations. Qualitative non-invasive µXRF results allowed for categorisation of the glazes and ceramic bodies based on their overall composition. Quantitative analysis by SEM/EDX on a subset of the samples delivered detailed results on the bodies and glazes. Tiles, made from clay or stonepaste, were almost exclusively decorated with a mixed alkaline lead glaze. The PbO content of this type of glaze ranged from 8 wt% to 25 wt%. The clay bodies of some tiles corresponded to the material of the locally used kiln furniture. Moreover, glaze res...
A Spanish 'set' of silver and silver-gilt liturgical furnishings from the Hospital de la Vera Cru... more A Spanish 'set' of silver and silver-gilt liturgical furnishings from the Hospital de la Vera Cruz at Medina de Pomar, near Burgos, Spain in the collection of the British Museum is recorded as being midfi ft eenth century in date. Doubts, however, were expressed about the disparities in style and decoration of the pieces, the construction methods and, therefore, the attribution and date of the set. As part of a reassessment of the collection in preparation for a new Medieval gallery, conservation treatment, a technical examination and a scientifi c analysis were undertaken. Th e conservation treatment principally consisted of removing an old protective coating with solvents. Where possible the objects were dismantled to assist the treatment and examination. Details of construction, tool marks, wear and old restoration were recorded. All pieces except the paten show evidence of either repair or alteration. Scientifi c examination of the enamels was carried out by X-ray fl uorescence spectrometry. Th e presence of chromium and the high lead content of the glass in some of the enamels are typical of nineteenthcentury enamelling, confi rming that alterations were made to the set during this period. Th e stylistic evidence, taken in conjunction with documentary evidence, technical examinations and scientifi c results, indicate that the seven pieces appear to have been 'enhanced' at some stage in the nineteenth century to form the present 'set' .
A Spanish 'set' of silver and silver-gilt liturgical furnishings from the Hospital de la Vera Cru... more A Spanish 'set' of silver and silver-gilt liturgical furnishings from the Hospital de la Vera Cruz at Medina de Pomar, near Burgos, Spain in the collection of the British Museum is recorded as being midfi ft eenth century in date. Doubts, however, were expressed about the disparities in style and decoration of the pieces, the construction methods and, therefore, the attribution and date of the set. As part of a reassessment of the collection in preparation for a new Medieval gallery, conservation treatment, a technical examination and a scientifi c analysis were undertaken. Th e conservation treatment principally consisted of removing an old protective coating with solvents. Where possible the objects were dismantled to assist the treatment and examination. Details of construction, tool marks, wear and old restoration were recorded. All pieces except the paten show evidence of either repair or alteration. Scientifi c examination of the enamels was carried out by X-ray fl uorescence spectrometry. Th e presence of chromium and the high lead content of the glass in some of the enamels are typical of nineteenthcentury enamelling, confi rming that alterations were made to the set during this period. Th e stylistic evidence, taken in conjunction with documentary evidence, technical examinations and scientifi c results, indicate that the seven pieces appear to have been 'enhanced' at some stage in the nineteenth century to form the present 'set' .
This paper discusses a methodology that involves the use of x‐ray fluorescence (XRF), high energy... more This paper discusses a methodology that involves the use of x‐ray fluorescence (XRF), high energy particle induced x‐ray emission (HE‐PIXE) and particle induced γ‐ray emission (HE‐PIGE) spectroscopies for the study of historic denars with the aim of describing the advantages and limitations of each technique as well as arriving at an archaeometric interpretation of the compositions. Thirty nine medieval Polish denars minted by Kings Bolesław the Brave and Mieszko II Lambert were analysed for their elemental composition. While XRF is limited to the analysis of the material close to the object´s surface, high energy ion beam analysis was used to obtain information from Cu at a relatively larger depth. The major elements detected were Ag and Cu, while the minor elements were Pb, Au, Bi, and Zn. An evaluation of the results obtained with the different techniques shows that the content of Cu near the surface is different from the bulk composition of the coins. The obtained elemental composition was used to proliferate the understanding of chronological changes in the production of early medieval Polish denars.
Naturwissenschaftliche Informationen, insbesondere die chemische Zusammensetzung der Objekte, kön... more Naturwissenschaftliche Informationen, insbesondere die chemische Zusammensetzung der Objekte, können Hinweise auf die Hintergründe der Objektherstellung liefern, die der alleinigen kunsthistorischen Begutachtung verborgen blieben. Es können nicht nur Fragen nach dem Prozess, Zeitpunkt und Ort der Herstellung beantwortet werden. Die chemische Analyse gibt auch Hinweise auf Ereignisse und Veränderungen, die erst nach der Fertigstellung des Objektes erfolgten. So werden Alterungsphänomene oder historische Überarbeitungen und Restaurierungen aufgedeckt, aber auch Konservierungsstrategien zur Erhaltung der Kunstwerke unterstützt. Durch den technologischen Fortschritt im Bereich der röntgenanalytischen Methoden, die berührungsfrei, ohne Probennahme und ohne Schädigung für das Untersuchungsobjekt arbeiten, erschließen sich dem Analytiker erstmalig Möglichkeiten, auch sehr wertvolle und fragile Objekte zerstörungsfrei zu untersuchen.
French enamellers active in Limoges during the late fifteenth to the early seventeenth century we... more French enamellers active in Limoges during the late fifteenth to the early seventeenth century were noted for their fine painted scenes taken from classical mythology and Christian traditions. The forms made in the Limoges workshops included plaques, plates of various sizes, ewers and ewer stands, salt cellars, candlesticks and footed bowls, all of which were intended to be decorative rather than functional. Instead of the more obvious painted enamel surfaces, this study examines the metalwork of these vessels. The metal, entirely hidden beneath the enamel, is generally of sheet copper. While the study of damaged objects reveals constructional features, X-radiography of unaltered enamels, complemented by examination using a microscope and boroscope, has made it possible to understand the construction of the more complex shapes. The methods used to join the components are quite unlike those seen in sheet metalwork that was not intended for enamelling, and are partly explained by the ...
Non-European dyed materials other than textiles have received comparatively little systematic ana... more Non-European dyed materials other than textiles have received comparatively little systematic analysis, this is particularly true for objects made with dyed porcupine quills. This paper presents a comprehensive study of a group of Athapaskan porcupine quill specimens collected in 1862 which are held within the collections of National Museums Scotland, UK. Due to sampling limitations micro-destructive testing, or non-invasive analysis using PDA-UPLC, Raman Spectroscopy and PIXE were used to characterise the dye sources and metallic mordants. RBS was used to obtain additional information on the depth-profiling of the mordants in the keratin-based quill. The sensitivity of the quill specimens to photo-degradation was evaluated using Micro Fade Testing (MFT). The results from this multi-analytical study will be used to inform future display regimes of this unique collection.
The recovery of the Dacian gold bracelets was the most thrilling archaeological event of the last... more The recovery of the Dacian gold bracelets was the most thrilling archaeological event of the last years in Romania. The artefacts are exhibited in the Historical Treasure section of the National History Museum of Romania, Bucharest, being recovered from the international antique markets through a concerted effort of the Romanian, French, and German authorities. This paper reviews the X-Ray Fluorescence (XRF) analyses carried out on these exquisite artefacts. These measurements followed the visual examination of qualified experts, which concluded that the gold spiralled bracelets showed strong stylistic similarities with the Dacian silver bracelets discovered until that date in archaeological contexts. Since the most likely source-for geographical and historical reasons-for the metal used to manufacture these artefacts was the Transylvanian Apuseni mountains, additional measurements on several fragments of natural Transylvanian gold, both from placers and primary deposits, were performed using Synchrotron Radiation X-ray Fluorescence (SR-XRF) at the BESSY synchrotron, Berlin, and micro Particle Induced X-ray Emission (micro-PIXE) at the AGLAE accelerator, Paris, and at the AN2000 accelerator of LNL, Padova. The conclusion of this study was that the recovered spirals are genuine Dacian artefacts, made by cold hammering, chiselling and punching Transylvanian unrefined gold-gold panned from riverbeds mixed with primary gold, most likely extracted from surface veins. Résumé : La saisie des bracelets en or de Dacie a été un des événements archéologiques les plus remarquables de ces dernières années en Roumanie. Les objets sont exposés dans le Trésor Historique du Musée National d'Histoire de Roumanie, Bucarest, et ont été récupérés du marché international d'antiquités grâce aux efforts concertés des autorités Roumaines, Françaises et Allemandes. Cet article fait le bilan de l'analyse de ces objets exquis, réalisée par fluorescence à rayons X (FX). Ces mesures suivent l'examen visuel par des experts qualifiés qui ont conclu que les bracelets en or à spirales montrent des similitudes stylistiques fortes avec les bracelets en argent de Dacie découverts en contexte archéologique. Comme pour des raisons historiques et géographiques la source la plus probable du métal utilisé pour la fabrication de ces objets se trouve dans les Carpates transylvaniens, des mesures complémentaires ont été réalisées sur différents fragments d'or natif de Transylvanie, provenant tant de placers comme de
... For this reason, and because of the general problem of surface deterioration mentioned above,... more ... For this reason, and because of the general problem of surface deterioration mentioned above, the ... flat plaques or medallions, where on the reverse side no pictorial scene is painted, a so ... in the object caused by the different thermal expansions coefficients of the copper and the ...
To hinder the phenomenon of weathering of ancient stained glass, the present work proposes the ap... more To hinder the phenomenon of weathering of ancient stained glass, the present work proposes the application of sol-gel coatings to the glass surface. Previous investigations [1-6], in fact, show that sol-gel silica coatings do not change the appearance of artistic glasses when deposited on their surface. Moreover, the film thickness is so small (around 200 nm) and its composition and structure so compatible with that of the original glass, that the characteristics of the coating and original glass are not distinguishable. In this work, several recipes used to produce sol-gel coatings have been tested in order to understand their behavior when adopted for covering ancient weathered glass. The coatings are made of sol-gel silica prepared with two different catalysts: H + , Pb 2+ and without catalyst. All the investigated samples show a good adhesion of the coating to the glasses used to simulate the behavior of ancient artefacts. The sol-gel silica coatings have been studied before and after accelerated ageing to test the resistance of the protective coatings to weathering. Another important index to test of the efficiency of the sol-gel coatings for the protection of an ancient glass is the lead ion mobility. In ancient stained glass, in fact, this element is present in the metallic lead network, in the grisaille paintings and constitutes a main component of many glass tesserae. The action of water on this highly mobile ion involves the degradation of the glass itself and the release of the ion in the rain solution. Ageing tests show the efficiency of H + and Pb 2+ catalyzed coatings and the inefficiency of the non-catalyzed sol-gel layers.
The salt [Na.15-crown-5][Ni(mnt) 2 ].H 2 O has been prepared by electrocrystallisation and charac... more The salt [Na.15-crown-5][Ni(mnt) 2 ].H 2 O has been prepared by electrocrystallisation and characterised by X-ray crystallography showing a stacking arrangement of [Ni(mnt) 2 ] À and a slipped stack arrangement of the crown ethers.
Applied Physics A g. padeletti 1,u g.m. ingo 1 a. bouquillon 2 s. pages-camagna 2 m. aucouturier ... more Applied Physics A g. padeletti 1,u g.m. ingo 1 a. bouquillon 2 s. pages-camagna 2 m. aucouturier 2 s. roehrs 2 p. fermo 3
STAR: Science & Technology of Archaeological Research, 2019
Cobalt was commonly used as a colourant in the Egyptian glass industries of the 18th dynasty, dar... more Cobalt was commonly used as a colourant in the Egyptian glass industries of the 18th dynasty, dark blue glass being a regular find at palatial and settlement sites, including Amarna and Malqata. The main source of cobalt ore used during this period has been identified in the Egyptian western desert, around the oases of Kharga and Dakhla. In order to better understand the chaîne opératoire of Late Bronze Age glass production and-working, in particular with regard to cobalt ore, at Amarna, chemical analysis by portable X-Ray fluorescence was carried out in the field. This was done on contextualised archaeological material excavated at the site of Amarna, which cannot be exported from Egypt for analysis. The results of this study demonstrate how cobalt ore was used in the various known workshop sites at Amarna, resulting in a deeper understanding of raw materials use and exchange across this settlement.
Bodies and glazes of tiles from the Ilkhanid period found at the UNESCO World Heritage site of Ta... more Bodies and glazes of tiles from the Ilkhanid period found at the UNESCO World Heritage site of Takht-e Soleyman were studied to identify materials and certain technical characteristics of the architectural ceramics as part of a larger project to establish different productions. In addition, ceramic vessels and technical ceramics excavated at the site were analysed for comparison. µXRF, SEM/EDX, and Raman spectroscopy were used for the material investigations. Qualitative non-invasive µXRF results allowed for categorisation of the glazes and ceramic bodies based on their overall composition. Quantitative analysis by SEM/EDX on a subset of the samples delivered detailed results on the bodies and glazes. Tiles, made from clay or stonepaste, were almost exclusively decorated with a mixed alkaline lead glaze. The PbO content of this type of glaze ranged from 8 wt% to 25 wt%. The clay bodies of some tiles corresponded to the material of the locally used kiln furniture. Moreover, glaze res...
A Spanish 'set' of silver and silver-gilt liturgical furnishings from the Hospital de la Vera Cru... more A Spanish 'set' of silver and silver-gilt liturgical furnishings from the Hospital de la Vera Cruz at Medina de Pomar, near Burgos, Spain in the collection of the British Museum is recorded as being midfi ft eenth century in date. Doubts, however, were expressed about the disparities in style and decoration of the pieces, the construction methods and, therefore, the attribution and date of the set. As part of a reassessment of the collection in preparation for a new Medieval gallery, conservation treatment, a technical examination and a scientifi c analysis were undertaken. Th e conservation treatment principally consisted of removing an old protective coating with solvents. Where possible the objects were dismantled to assist the treatment and examination. Details of construction, tool marks, wear and old restoration were recorded. All pieces except the paten show evidence of either repair or alteration. Scientifi c examination of the enamels was carried out by X-ray fl uorescence spectrometry. Th e presence of chromium and the high lead content of the glass in some of the enamels are typical of nineteenthcentury enamelling, confi rming that alterations were made to the set during this period. Th e stylistic evidence, taken in conjunction with documentary evidence, technical examinations and scientifi c results, indicate that the seven pieces appear to have been 'enhanced' at some stage in the nineteenth century to form the present 'set' .
A Spanish 'set' of silver and silver-gilt liturgical furnishings from the Hospital de la Vera Cru... more A Spanish 'set' of silver and silver-gilt liturgical furnishings from the Hospital de la Vera Cruz at Medina de Pomar, near Burgos, Spain in the collection of the British Museum is recorded as being midfi ft eenth century in date. Doubts, however, were expressed about the disparities in style and decoration of the pieces, the construction methods and, therefore, the attribution and date of the set. As part of a reassessment of the collection in preparation for a new Medieval gallery, conservation treatment, a technical examination and a scientifi c analysis were undertaken. Th e conservation treatment principally consisted of removing an old protective coating with solvents. Where possible the objects were dismantled to assist the treatment and examination. Details of construction, tool marks, wear and old restoration were recorded. All pieces except the paten show evidence of either repair or alteration. Scientifi c examination of the enamels was carried out by X-ray fl uorescence spectrometry. Th e presence of chromium and the high lead content of the glass in some of the enamels are typical of nineteenthcentury enamelling, confi rming that alterations were made to the set during this period. Th e stylistic evidence, taken in conjunction with documentary evidence, technical examinations and scientifi c results, indicate that the seven pieces appear to have been 'enhanced' at some stage in the nineteenth century to form the present 'set' .
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