Metallic and Translucent Decorative Layers: Analytical and Historical Insights from the Medieval Sculptural Complex of the Refectory of San Salvador de Oña (Burgos, Spain)

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

• According to Heritage's policy on free format submission, manuscripts must still include all required sections clearly labelled including Materials & Methods, Results, and Conclusions, among others. I would recommend revising the manuscript structure to ensure these key sections are distinctly separated and titled accordingly. For instance, the methodological content currently placed under "Methodology and analysis" should ideally be renamed to "Materials & Methods", and any results or interpretations should be placed under a clearly defined "Results" section. Additionally, please ensure that methodological and analytical content is not embedded within the Introduction, but instead presented in the appropriate dedicated section. This will make the manuscript more readable and help highlight the strength of the research more effectively.

• Figure 1. To get a better overview, I think it would be good if the author labelled the images with corresponding descriptions (Arch 1, 2, 3, 4 and 5; Capitals and capital tops arch 1, 2,3,4). Even though the corresponding labels are in the captions, you have to constantly scroll up and down to see what the captions say.

  Figure 2. It is worth considering whether the preserved relief fragments can be drawn in here using a frame and the corresponding label.

  Figure 3. Figure 3 is a very nice drawing, but without a legend it makes little sense. Here, too, all parts should be labelled accordingly.

  Figure 4. (a) Unfortunately, the presence of cuts in the tin foils is not immediately apparent to someone seeing this for the first time. (b) Tin foil edges with obvious oxidation – this probably refers to a corner in the blue area, but I am not sure, as not only the edges but the entire surface is oxidised.

  Figure 5/6/7. Here, too, the legend/explanation is missing.

• Since international readers may not necessarily be familiar with the Monastery of San Salvador de Oña, it would be advisable to mention the country for ease of understanding.
• I am not a fan of Table 2. The text does not need to be fully formulated; it is an overview and this must be visible at first glance in a table, without the reader getting lost in the text again. The descriptions in the text are already long and with so many samples it is not easy to maintain an overview. Furthermore, the results are only evaluated qualitatively and not quantitatively. If EDX has already been done, then I would like to see the percentage contribution of individual elements. Otherwise, it is impossible to grasp the meaning of the description ‘high concentration in consecutive layers of chlorine and copper’.

Comments on the Quality of English Language

Although the manuscript contains detailed technical information, the language is sometimes overly complex and unnecessarily verbose. This can impair comprehensibility for the reader. Many sentences are long and highly convoluted, and the style occasionally relies on redundant or exaggerated expressions (e.g. ‘it is noteworthy that’, ‘enables the formulation of a comprehensive analysis’).

Author Response

Comments 1: According to Heritage's policy on free format submission, manuscripts must still include all required sections clearly labelled including Materials & Methods, Results, and Conclusions, among others. I would recommend revising the manuscript structure to ensure these key sections are distinctly separated and titled accordingly. For instance, the methodological content currently placed under "Methodology and analysis" should ideally be renamed to "Materials & Methods", and any results or interpretations should be placed under a clearly defined "Results" section. Additionally, please ensure that methodological and analytical content is not embedded within the Introduction, but instead presented in the appropriate dedicated section. This will make the manuscript more readable and help highlight the strength of the research more effectively.

Response 1: Thank you for pointing this out. I agree with this comment. Therefore, I have revised the structure of the artichle following the indications provided by Reviewer 1. The final version of the article has being organized into the sections: Introduction, Historical approach, Materials and Methods, Results, Discussion and Hypotheses, and Conclusions.

Comments 2: Figure 1. To get a better overview, I think it would be good if the author labelled the images with corresponding descriptions (Arch 1, 2, 3, 4 and 5; Capitals and capital tops arch 1, 2,3,4). Even though the corresponding labels are in the captions, you have to constantly scroll up and down to see what the captions say. Figure 2. It is worth considering whether the preserved relief fragments can be drawn in here using a frame and the corresponding label. Figure 3. Figure 3 is a very nice drawing, but without a legend it makes little sense. Here, too, all parts should be labelled accordingly. Figure 4. (a) Unfortunately, the presence of cuts in the tin foils is not immediately apparent to someone seeing this for the first time. (b) Tin foil edges with obvious oxidation – this probably refers to a corner in the blue area, but I am not sure, as not only the edges but the entire surface is oxidised. Figure 5/6/7. Here, too, the legend/explanation is missing.

Response 2: Agree. I have, accordingly, revised all the figures and descriptions to emphasize this point. Figure 1 has been divided into the arches (Figure 1) and the capitals (Figure 2) in order to provide clearer descriptions of the images without requiring the reader to move extensively through the text. The use of Figure 2 (now figure 3) is intended to illustrate an interpretation lacking material basis, since neither surviving remains nor architectural evidence allow us to confirm that the interpretation proposed in the 1970s is correct. This figure has been deleted to avoid bad interpretations or complications in the reading. In the previous figure 3, a brief description has been added of the shaded areas and their exact correspondence, with the aim of clarifying the presence of the metals detected. In the previous figure 4, a more detailed description of the tin cuts and oxidation has been included, and the images have been modified by adding a small red marker indicating these patterns. In the previous figures 5/6/7, descriptions of the colors corresponding to the metals identified and detected have been added.

Comments 3: Since international readers may not necessarily be familiar with the Monastery of San Salvador de Oña, it would be advisable to mention the country for ease of understanding.

Response 3: Agree. I have, accordingly, added the correct references to the country to emphasize this point. References to the location of Oña in Burgos, Spain have been added in order to geographically contextualize the piece. Even the title has been changed to facilitate the reading and undestanding.

Comments 4: I am not a fan of Table 2. The text does not need to be fully formulated; it is an overview and this must be visible at first glance in a table, without the reader getting lost in the text again. The descriptions in the text are already long and with so many samples it is not easy to maintain an overview. Furthermore, the results are only evaluated qualitatively and not quantitatively. If EDX has already been done, then I would like to see the percentage contribution of individual elements. Otherwise, it is impossible to grasp the meaning of the description ‘high concentration in consecutive layers of chlorine and copper’.

Response 4: Agree. I have, accordingly, modified the data of the tables to emphasize this point. The tables have been reformulated to include the reference layer analyzed, which had not been previously indicated, as well as the percentage of each compound detected.

4. Response to Comments on the Quality of English Language

Point 1: Although the manuscript contains detailed technical information, the language is sometimes overly complex and unnecessarily verbose. This can impair comprehensibility for the reader. Many sentences are long and highly convoluted, and the style occasionally relies on redundant or exaggerated expressions (e.g. ‘it is noteworthy that’, ‘enables the formulation of a comprehensive analysis’).

Response 1: All the text has been translated again reducing the extension of the sentences. 

Thank you so much for the effort an time spent in this review. I tried to improve the text the best I could.

Reviewer 2 Report

Comments and Suggestions for Authors

This study investigates the materials and decorative techniques used in the Monastery of San Salvador de Oña’s refectory, focusing on tin leaf applications and Nasrid influences. Analytical methods, including SEM-EDX and microscopic analysis, reveal widespread use of tin sheets, gilding, and organic binders such as linseed oil and rosin resin. The presence of metallic layers, especially tin, copper, and lead, shows signs of corrosion and deterioration, indicative of extensive aging and environmental exposure. The research highlights the technical complexity of the ensemble, demonstrating a blend of Christian, Islamic, and Nasrid artistic influences, notably in decorative motifs and materials. The findings establish a significant artistic connection between the monastery and Nasrid culture, exemplified through material analysis and stylistic features, underscoring its unique historical and cultural importance.

Firstly, the article employs an interdisciplinary approach combining material characterization techniques—such as scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR)—to analyze the polychrome and metallic remains of the sculptural ensemble in the refectory of San Salvador de Oña. This scientific methodology allows precise identification of materials like tin sheets, pigments, and varnishes, providing insight into the technical procedures used in the medieval decoration.

Secondly, the methodology is robust and appropriate given the research objectives. The integration of analytical techniques with historical sources and technical treatises demonstrates a comprehensive approach that enhances the reliability of the findings.

Thirdly, the article situates its research within the broader historiographical framework of medieval Iberian art, emphasizing the significance of monastic decoration and cultural exchanges between the Nasrid Kingdom and Castile. It addresses existing debates about the dissemination of artistic techniques and materials, especially in relation to the influence of Islamic craftsmanship and their integration into Christian monastic contexts. While it effectively references previous studies on medieval decorative arts and materials, it also contributes new insights by connecting material findings directly with historical and cultural motivations, such as the political-legitimizing strategies of the Castilian monarchy.

Fourthly, the originality of the article lies in its focus on the materiality of the polychrome and metallic layers in a specific, highly significant monastic setting—an aspect that has been relatively underexplored in Iberian medieval art studies. The application of advanced scientific methods to a context-rich historical monument allows for a nuanced understanding of medieval artisanship and technological transfer. Furthermore, uncovering the use of tin sheets as a decorative element and linking these techniques with historical influences from Nasrid craftsmanship offers a fresh perspective on material innovation and cultural interactions.

          Therefore, the article advances knowledge by providing detailed material and technical data on medieval polychrome decoration; demonstrating the use of tin sheets as a decorative layer, highlighting technical experimentation and adaptation; contextualizing material choices within the political and cultural framework of the 14th-century Castilian court and Islamic influences, and highlighting the transfer and adaptation of Islamic craft techniques into Christian monastic art, contributing to discussions on cultural hybridity and cross-cultural exchanges. These new contributions are valuable for specialists in medieval art, conservation science, and historical studies.

Minor improvements in English:

The writing style is academic, clear, and well-structured. Technical descriptions are precise, and the integration of scientific data with historical narrative is seamless.

In conclusion, the study seamlessly integrates scientific analysis with historical interpretation, utilizing advanced analytical techniques that yield concrete, data-driven results. Focused on a unique and significant monument, the research adds considerable value to regional medieval studies by highlighting its cultural and artistic importance. Additionally, the study contributes to conservation science by thoroughly documenting the material compositions, which are vital for ongoing preservation efforts. The work is well-referenced within the existing literature, demonstrating a thorough and scholarly approach that underscores its academic rigor and comprehensive understanding of the subject. This is a well-executed, original contribution that combines scientific and historical perspectives to deepen understanding of medieval monastic decoration. Therefore, the article possesses significant scholarly merit and meets the criteria for publication, pending minor editorial refinements for clarity and style in English language.

Comments on the Quality of English Language

There are minor points for improvement in clarity and flow of the English language, but overall, the style supports effective communication of the complex interdisciplinary research.

For instance, there are some phrases and paragraphs whose style in English could be improved, along with suggestions for enhancement:

1. Century references may be expressed using Arabic numerals (e.g., 12th century) or written out in full (e.g., twelfth century), but consistency should be maintained throughout the text. (in line 27: 16th century, but in line 527: fifteenth century)
2. Phrases that could be improved: 

Original: "While it is true that this technical process may not achieve excellence in its placement due to the clear deterioration that can be observed in these metallic layers, it is nonetheless possible to highlight how, in spite of these vicissitudes, this piece is a national reference, of which no similar examples have been found." (lines: 1015-1018)

Suggested improvement: "Although this technical process may not attain perfect placement due to evident deterioration in the metallic layers, it is nonetheless noteworthy that this piece remains a national benchmark, with no similar examples known."

Original: "The presence in this monastic context of techniques of clear Nasrid origin, in addition to materials such as copper resinates on tin and iconographic elements of the ensemble, such as the frieze of Kufic writing with praises, serves to establish a clear artistic connection with the Reales Alcazars of Seville. In this manner, it is imperative to contemplate the manner in which a decorative period in Oña is situated in the 14th century, drawing directly from the distinctive artistic milieu that encompasses Nasrid influences from Granada and Christian tradition, and implements them through the intricate legitimizing program of Pedro I and, by extension, the figure of his chaplain Lope Ruiz, abbot of Oña." (lines: 1019-1026)

Suggested improvement: "The presence of techniques with clear Nasrid origins, along with materials like copper resinates on tin and iconographic elements such as Kufic inscriptions, establishes a definitive artistic link to the Reales Alcazares of Seville. Consequently, it is essential to consider how the decorative program in Oña, situated in the 14th century, directly draws from the distinctive artistic milieu blending Nasrid influences from Granada with Christian tradition. This synthesis is vividly manifested through the intricate legitimizing themes associated with Pedro I and his chaplain, Lope Ruiz, abbot of Oña."

Original: "The significance of the study of the metal sheets in the refectory complex is that it has facilitated an understanding of medieval decorative techniques. Verification has been undertaken to establish the manner in which the material evidence of this set communicates a punctual correlation with certain extant recipes from the technical-artistic continental treatises dating back to the VIII century." (lines 953-957)

Suggested improvement: "Studying the metal sheets in the refectory complex has been crucial in deepening our understanding of medieval decorative techniques. This research has verified that the material evidence aligns closely with certain known recipes from continental treatises on technical and artistic practices dating back to the 8th century."

Original: "This phenomenon of experiential transmission of professional knowledge over the centuries is evidenced by the adaptation and slight modification of the techniques employed according to the particular hands and conditions that contextualize the execution of the different works. The significance of this liberty in terms of workmanship, experience, and knowledge is widely recognized in technical applications and artistic processes." (lines: 989-994)

Suggested improvement: "The transmission of professional knowledge over the centuries is evidenced by the adaptation and slight modifications of techniques, tailored to the specific skills and conditions of individual artisans. This flexibility in craftsmanship and technique reflects a recognized tradition of experiential learning, contributing significantly to both technical applications and artistic expression."

These improvements aim to enhance clarity, formality, and fluency, aligning the style more closely with academic writing in English.

Author Response

Point 1: Century references may be expressed using Arabic numerals (e.g., 12th century) or written out in full (e.g., twelfth century), but consistency should be maintained throughout the text. (in line 27: 16th century, but in line 527: fifteenth century)

Response 1: Agree. All the data terms has been revised and unified as Arabic numerals. 

All the article has been translated again to improved the English, I took note about the reviewer's suggestions and applied them in the new translation when It has been possible. Thank you so much for the effort and the improvements. 

Reviewer 3 Report

Comments and Suggestions for Authors

This is an interesting and well-planned work that combines a rigorous study of medieval art with artistic materiality, an aspect that is often overlooked. In addition, it studies a unique work of art, namely the sculptural ensemble in the refectory of Oña, about which there is almost no scientific literature and everyone repeats the same things. Despite this, the work needs a few minor revisions, which the author can make to adjust his work, all of them minor.

Here are some suggestions:

• The author has used the Spanish term ‘corlado’. Although the artwork is Spanish and the author may also be Spanish, we should use the appropriate English terminology when referring to this term. In historical treatises on art and decorative techniques in English, you might find phrases such as: ‘...a yellow-tinted varnish was applied over silver to imitate gilding...’ or ‘...a transparent gold varnish (called colradura in Spanish) used in colonial silversmithing...’. You can use ‘gold-tinted varnish’ or even ‘vernis doré’ (borrowed from French in some old English texts). But you shouldn't use corlado, except as an explanation when appropriate, and definitely not in the title. The same goes for the use of technical terms in Spanish and English throughout the text (e.g., ‘tin foils’ vs. ‘hojas de estaño’).
• The title is presented with the expression ‘Reflections of divinity’. The use of reflections undoubtedly has to do with technique. However, the reference to divinity is not understood, since the iconographic programme represented the Last Supper. It should be replaced by a more specific expression that maintains the same force.
• You should review the use of capital letters throughout the document, which seems random. For example, in the sentence ‘substantial number of medieval, Renaissance and Baroque artistic remains’, it is not clear why ‘Medieval’ is not capitalised.
• The introduction to the article is somewhat scattered; it is not clear from the outset what the working hypothesis is or what the specific objectives of the article are. This issue should be clarified. In addition, there is no section that serves as a clear overview of the state of the art and organises the previous references, both on the use of metals and corlad in medieval sculpture and on the collection itself. At the end of this section, the specific contribution of this work, which is rather unclear, should be made clear. The discussion mixes results with methodological description, making it difficult to separate the interpretation of the data from the technical exposition. I also have the feeling that there is some repetition of content (e.g., descriptions of historical techniques) that could be condensed or placed in an appendix.
• As for the methodology of the article, the sampling strategy should be much clearer and more explicit: the criteria for selecting the 45 points, justification of why some areas were analysed and others were not. It is also acknowledged (lines 171-173) that some analyses were carried out ‘without exact indications of areas or materials’, which weakens the validity of the results; this should be discussed as a serious limitation of the work. Nor is there any detail on the calibration, replication or quality control of the instrumental techniques (SEM-EDX, FTIR, XRD, etc.) that require it. These studies also lack a precise description of data processing and material identification criteria (e.g., thresholds for determining the significant presence of an element).
• As for the results, the tables could be improved, as they are not standardised and contain a mixture of descriptions, interpretations and raw data without a clear format. Most of them could be summarised and made clearer. We have also noticed that the sample codes are not explained in an initial legend, forcing the reader to deduce their meaning. As for the microphotographs and distribution maps (e.g., Figures 5-7), they should always be presented with a scale to be valid. It would also be interesting to quantify the degree of metal coverage statistically (terms such as ‘almost the entire surface’ are used without a precise percentage derived from objective measurement).
• Regarding the interpretation and discussion of the results, it is recommended that some interpretative statements that do not have sufficient direct correlation with the analytical data be revised (e.g., the ‘applied brocade’ hypothesis in lines 388-390 without confirmation of binders). I also have the impression that historical sources are cited extensively, but sometimes without explicit connection to specific material findings. In many cases, the relationship between the historical-artistic context and the analytical results is more descriptive than analytical; there is a lack of comparative hypotheses with other similar sets studied using modern techniques. It would also be interesting to discuss the possible bias introduced by the differential degradation of materials (gold vs. tin) in the interpretation of decorative phases.
• There are other important stylistic issues: the text is overloaded with long, verbatim quotations from historical sources that interrupt the flow of reading and could be greatly summarised. There are also numerous overly long sentences with excessive parenthetical phrases that make comprehension difficult. Bibliographic references with irregular formatting have also been detected; standardisation according to the journal's style is lacking.
• As for the conclusions, we believe that the key findings are not summarised in a compelling manner, nor does it prioritise original contributions over previous literature; rather, it repeats technical information already presented. There is also a lack of critical analysis of the methodological limitations acknowledged in the body of the text (e.g., sampling without exact indications, absence of complete characterisation of binders). We also feel that the dating of decorative phases is presented as a statement, but without sufficient explicit correlation with external comparative analyses or contemporary archival documentation: these statements need to be reinforced.
• There is also a lack of contribution to the discussion on the impact of the findings on the future conservation of the site or its integration into restoration strategies. Furthermore, there is a lack of comparison of the results with alternative hypotheses in the historiography of Oña, which weakens the interpretative value.
• Finally, the article's funding refers to a project from more than 10 years ago that has already been completed. Although some of the chemical samples are due to that project, the funding section should refer to active or recently completed projects. Perhaps it could be mentioned in the acknowledgements.

Once these minor corrections have been made, the paper will be ready for publication in this prestigious journal.

Author Response

Comments 1: The author has used the Spanish term ‘corlado’. Although the artwork is Spanish and the author may also be Spanish, we should use the appropriate English terminology when referring to this term. In historical treatises on art and decorative techniques in English, you might find phrases such as: ‘...a yellow-tinted varnish was applied over silver to imitate gilding...’ or ‘...a transparent gold varnish (called colradura in Spanish) used in colonial silversmithing...’. You can use ‘gold-tinted varnish’ or even ‘vernis doré’ (borrowed from French in some old English texts). But you shouldn't use corlado, except as an explanation when appropriate, and definitely not in the title. The same goes for the use of technical terms in Spanish and English throughout the text (e.g., ‘tin foils’ vs. ‘hojas de estaño’).

Response 1: Thank you for pointing this out. I agree with this comment. Therefore, I have changed those therms in accordance with the indications of Reviewer 3. The term corladura has been modified since, although it is indeed Spanish, it may be more generally rendered as color-varnish, given that there is no exact English equivalent for what we are dealing with. However, in the citation of De la Fuente in section 2.3.2, the choice of the term corla over others is explained in relation to the metallic support. Therefore, from that point onwards, this term will be consistently used throughout the text. It should be noted, however, that the terms suggested by the reviewer are not entirely accurate, as they are used exclusively when the final color of the glaze is yellow or golden, whereas in this case it is green, making it impossible to apply such terminology. In addition, the term tin foils has been replaced with tin leafs to avoid problems of material identification

Comments 2: The title is presented with the expression ‘Reflections of divinity’. The use of reflections undoubtedly has to do with technique. However, the reference to divinity is not understood, since the iconographic programme represented the Last Supper. It should be replaced by a more specific expression that maintains the same force.

Response 2: Agree. I have, accordingly, modified the title to emphasize this point. The previous choice of Reflections of Divinity is based on the use of metals, the brilliance of gold, and its symbolism in the Middle Ages. The title has been changed to emphasized the topic of the study: the metallic and traslucent layers study and the historical and material approach. 

Comments 3: You should review the use of capital letters throughout the document, which seems random. For example, in the sentence ‘substantial number of medieval, Renaissance and Baroque artistic remains’, it is not clear why ‘Medieval’ is not capitalised.

Response 3: Agree. I have, accordingly, all terms have been reviewed, and a new translation has been carried out to solve these issues.

Comments 4: The introduction to the article is somewhat scattered; it is not clear from the outset what the working hypothesis is or what the specific objectives of the article are. This issue should be clarified. In addition, there is no section that serves as a clear overview of the state of the art and organises the previous references, both on the use of metals and corlad in medieval sculpture and on the collection itself. At the end of this section, the specific contribution of this work, which is rather unclear, should be made clear. The discussion mixes results with methodological description, making it difficult to separate the interpretation of the data from the technical exposition. I also have the feeling that there is some repetition of content (e.g., descriptions of historical techniques) that could be condensed or placed in an appendix.

Response 4: Agree. I have, accordingly, revised this questions to emphasize this point. The research objectives and the advances represented by this article and study have been introduced. The entire historical study has been consolidated into a “An Historic-Artistical approach ” with three sections addressing the monastery and the piece, the metallic materials, and the color-varnishes, while its length has been reduced. References to cited historical sources have been removed, keeping only their bibliographic citation. Some previously unclear methodological criteria have been more thoroughly established, and the results obtained have been presented in the Results section, leaving their interpretation for the Discussion section, combining elements from sections 2 and 4.

Comments 5: As for the methodology of the article, the sampling strategy should be much clearer and more explicit: the criteria for selecting the 45 points, justification of why some areas were analysed and others were not. It is also acknowledged (lines 171-173) that some analyses were carried out ‘without exact indications of areas or materials’, which weakens the validity of the results; this should be discussed as a serious limitation of the work. Nor is there any detail on the calibration, replication or quality control of the instrumental techniques (SEM-EDX, FTIR, XRD, etc.) that require it. These studies also lack a precise description of data processing and material identification criteria (e.g., thresholds for determining the significant presence of an element).

Response 5: Agree. I have, accordingly, revised all these questions to emphasize this point. The criteria for selecting sampling points have been explained (materials, location, contrast between arches, surface and internal contrasts, deterioration, or significant colors and materials that were organoleptically notable). Regarding the reference “without exact indications of zones or materials, which weakens the validity of the results; this should be discussed as a serious limitation of the work”: although it is true that the ArteLab laboratory did not allow the author to participate in the decision-making processes during sample analyses, as occurred with the CAI, the results obtained by ArteLab in all analyses were coherent. They were treated more cautiously than in the case of the CAI because, despite the detailed stratigraphies and analyses, the exact points of BSE and SEM application were unknown. This limitation may have caused some gaps in detection, which is why new samplings of the same zones and samples were later performed at the CAI to verify strata, materials, and techniques.
Details regarding equipment calibration, both at ArteLab and CAI, are provided in documents supplied by these institutions and on their websites (referenced now), which include quality control procedures. These details were not considered relevant to translate in the article, as these are professional institutions whose reliability is assumed. Regarding the CAI, which allowed greater flexibility, the INCA software and all sample data were provided to obtain the most relevant spectra and measurements, including calibrations, frequencies, and other key aspects, usually indicated alongside BSE and SEM reference images. ArteLab, on the other hand, produces interpreted reports based on all spectra, images, and analyses, in the same way that the author does with CAI data, always identifying materials according to the weight percentages in the quantitative analyses.

Comments 6: As for the results, the tables could be improved, as they are not standardised and contain a mixture of descriptions, interpretations and raw data without a clear format. Most of them could be summarised and made clearer. We have also noticed that the sample codes are not explained in an initial legend, forcing the reader to deduce their meaning. As for the microphotographs and distribution maps (e.g., Figures 5-7), they should always be presented with a scale to be valid. It would also be interesting to quantify the degree of metal coverage statistically (terms such as ‘almost the entire surface’ are used without a precise percentage derived from objective measurement).

Response 6: Agree. I have, accordingly, revised these questions to emphasize this point. The tables have been streamlined, including only quantitative data instead of interpretations that made them excessively long. The origin of the sample coding has been explained to make it easier for the reader to understand this terminology specific to the research. Although the figures corresponding to the distribution maps could not be redrawn with a scale due to time constraints, they now include a detailed description of the measurements per arch, which is expected to sufficiently address this issue. Regarding the metallic coating, the text specifies in several instances that these metallic surfaces cover approximately 80% of the ensemble.

Comments 7: Regarding the interpretation and discussion of the results, it is recommended that some interpretative statements that do not have sufficient direct correlation with the analytical data be revised (e.g., the ‘applied brocade’ hypothesis in lines 388-390 without confirmation of binders). I also have the impression that historical sources are cited extensively, but sometimes without explicit connection to specific material findings. In many cases, the relationship between the historical-artistic context and the analytical results is more descriptive than analytical; there is a lack of comparative hypotheses with other similar sets studied using modern techniques. It would also be interesting to discuss the possible bias introduced by the differential degradation of materials (gold vs. tin) in the interpretation of decorative phases.

Response 7: Agree. I have, accordingly, revised these questions to emphasize this point. The placement of references to historical-artistic sources has been revised to make the narrative clearer. The issue of applied brocade is always presented as a hypothesis to be tested in the future, not as a certainty, since current studies do not fully confirm it. While the use of tin sheets is documented in Europe and in Al-Andalus, in a much more limited context for decorative details, the remains at Oña do not correspond to what is known as applied brocade; rather, they represent the application of tin sheets in relief without textile imitation (BAZETA, NADOLNY, GONZALEZ, ROBERTO AMIEVA, etc.). This sentence has been modified for clarity. No comparative studies with other European ensembles exist because there are no artistic or technical references at this level, either due to lack of material preservation or the absence of such extensive surface remains as those at Oña.
Potential bias introduced by material degradation has been considered by analyzing the laminar structure of tin and gold, as well as the associated pigments, their composition, elemental percentages, and BSE images, allowing a more effective reconstruction of the different technical phases in which these metals were combined.

Comments 8: There are other important stylistic issues: the text is overloaded with long, verbatim quotations from historical sources that interrupt the flow of reading and could be greatly summarised. There are also numerous overly long sentences with excessive parenthetical phrases that make comprehension difficult. Bibliographic references with irregular formatting have also been detected; standardisation according to the journal's style is lacking.

Response 8: Agree. I have, accordingly, modified these questions to emphasize this point. All long quotations have been eliminated, and the main text has been streamlined by reducing historical references and lengthy descriptive sentences. The entire citation apparatus has been reviewed, and pagination references, which were previously incorrect, have been corrected.

Comments 9: As for the conclusions, we believe that the key findings are not summarised in a compelling manner, nor does it prioritise original contributions over previous literature; rather, it repeats technical information already presented. There is also a lack of critical analysis of the methodological limitations acknowledged in the body of the text (e.g., sampling without exact indications, absence of complete characterisation of binders). We also feel that the dating of decorative phases is presented as a statement, but without sufficient explicit correlation with external comparative analyses or contemporary archival documentation: these statements need to be reinforced.

Response 9: Agree. I have, accordingly, revised these questions to emphasize this point. The conclusions have been expanded to highlight the advances achieved. It is true that binder detection in the CAI samples is limited due to equipment constraints, but this limitation has been extensively referenced. The decorative phases are based on a doctoral thesis project, which involved comprehensive and relevant research, briefly reflected in the references added to the article. These investigations are more extensively discussed in other published articles where these issues are also explored in depth (see CUESTA, 2024).

Comments 10: There is also a lack of contribution to the discussion on the impact of the findings on the future conservation of the site or its integration into restoration strategies. Furthermore, there is a lack of comparison of the results with alternative hypotheses in the historiography of Oña, which weakens the interpretative value.

Response 10: Thank you for pointing this out. I agree with this comment. Therefore, I have considered that this article is already quite extensive, focusing solely on the study of the metal sheets and the applied glazes. I believe that the discussion on the impact of these findings on conservation or restoration strategies should be the subject of a separate article, dedicated exclusively to this topic, where the proposed strategies can be fully appreciated rather than being briefly and superficially addressed in a short section of this contribution.

Comments 11: Finally, the article's funding refers to a project from more than 10 years ago that has already been completed. Although some of the chemical samples are due to that project, the funding section should refer to active or recently completed projects. Perhaps it could be mentioned in the acknowledgements.

Response 11: Agree. I have, accordingly, erased the funding and added it into the acknowledgements to emphasize this point. 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I appreciate the authors’ thorough revisions in response to the previous comments. The manuscript has been substantially improved, with careful attention to clarity, coherence, and the issues raised. Overall, the revisions have strengthened the presentation, and I find the manuscript now much clearer and well-prepared.