Lucía Pereira Pardo (RyC, Incipit-CSIC) and Jitske Jasperse (RyC, IH-CSIC)
In this blog entry Lucía Pereira Pardo, heritage scientist, and Jitske Jasperse, art historian, talk about their project “Out of the Bag. Unravelling Medieval Seal Bags through Cultural Studies and Scientific Analysis”. They discuss their personal interests, asses the value of interdisciplinary collaboration and explain how they are trying to broaden their network.
Lucia: Some readers may think “Seal bags? Never heard of them”. So Jitske, how did you come across seal bags and what are they?
Jitske: To be honest Lucía I cannot remember exactly when I thought “wow, seal bags”. I encountered them while working on medieval wax seals that are attached to charters, but never paid real attention to them. At some point, my art historical research on the visibility and invisibility of artefacts sparked my interest in seal bags. These bags can be made of textile, flax fibres, parchment or leather and cover relatively fragile wax seals (Fig. 1). They were likely used to both protect the seals and visually distinguish important charters. The most sumptuous examples are made of fragments of fabric repurposed from older garments or furnishings. I find them so fascinating because they hide the very objects – that is, the wax seals – that originally were meant to be seen. In medieval society seals were extremely important because they were signs of validation and authentication of written agreements and exchanges. The National Archives (TNA) in the United Kingdom house some 70,000 of such medieval documents. Apart from the excitement of unwrapping the seal bags, some specimens are also appealing because of their stunning appearance. The precious gold and pink-red mussel-shaped silk envelope preserving the seal of Thomas Becket is such an example, which we discussed extensively in an earlier blog. I knew of more examples preserved at TNA, and it was through Paul Dryburgh, TNA’s Principal Record Specialist, and working on medieval material that I got in touch with you to suggest investigating their materiality.
Fig. 1 Selection of seal bags from The National Archives. From left to right: silk seal bag enveloping the seal of Thomas Becket; silk seal bag covering seal of Henry III; painted linen bag holding the seal of Edward I.
Jitske: And what about yourself, Lucía, had you ever heard of seal bags before we met and started discussing this project?
Lucía: Actually, I had come across the beautiful pink and gold seal bag you just mentioned (Fig. 1, left), when I analysed Becket´s wax seal ahead of a loan for the British Museum´s exhibition “Thomas Becket: murder and the making of a saint” in 2021. But back then my focus was mostly on the seal: differentiating original from restored parts, identifying the red pigment added to the wax, understanding the deterioration of the seal, imaging the fingerprint impressions left on the wax when still warm… I did admire the beautiful bag, but I thought it was a one-off, because of the importance of this particular seal, practically a relic! I was not aware that seal bags were relatively wide-spread in archives and libraries, at least in northern Europe, until we met and discussed putting together a collaborative project to investigate the materiality of these overlooked and fascinating objects. And as it happens, once I discovered the existence of seal bags, I keep finding more and more!
Jitske: Lucía, as a conservation scientist you have another approach to the seal bags at TNA than myself as an art historian. Can you tell us something about your role in the project? And what did you particularly like about the collaboration?
Lucía: As a heritage scientist, my role was to use scientific techniques to investigate the composition of the materials in a selection of twelve seal bags from TNA and other collections, and try to better understand how they were made and when, as well as their vulnerability and conservation needs. For instance, I examined the metal threads under the microscope, determined the type of fibre and dyes used in the textiles and studied their sensitivity to light.
What I enjoyed the most about the project “Out of the Bag” was working closely and learning from colleagues from other disciplines: archivists, historians, art historians, textile specialists. For instance, the discussions with textile expert Ana Cabrera were incredibly helpful all along the process. First, to determine the type of weave and decorative style of the textiles, which narrows down possible chronologies and geographical origins. This helped us to refine our research question to be answered through the material analysis: “where was this samite made (see central bag in figure 1): in the Iberian Peninsula or in a workshop in the Near East or Italy?” Second, to choose the best areas of the bags to be analysed. This is particularly important when sampling is very limited as with these valuable textiles. In our case we focused on analysing the red dyes because we expected this to be most helpful for determining the geographical origin of the textile. For example, kermes would point to an Iberian textile, whereas Armenian cochineal would suggest a workshop from the Eastern Mediterranean. After testing, the identification of sappanwood as the red dye used in the samite made us lean towards a Byzantine workshop from the Middle East.
This result triggered a new research question: “what does the use of sappanwood – an Eastern dye – mean in a drap d’areste made in the Iberian Peninsula or the south of France in the twelfth or thirteenth century?” Probably that global trade of this dye was actually occurring earlier than we thought! Such insights usually arise from collaboration.
Jitske: Great that you mention this teamwork, because this ties in to one of our ambitions to broaden the network of archivists and curators working with collections that may hold seal wrappings. Could you tell a bit more about this?
Lucía: Yes, we have started broadening the network. During this project we sought contact with the British Library and the London Metropolitan Archives. We visited them with our portable analytical equipment and examined some gorgeous and fascinating seal bags, including different textile techniques to those seen at TNA (Fig. 2). Raising awareness about the interest of the seal bags – among archivists, librarians, curators, conservators and readers – is key to locate more examples, keep learning about how they were made and used, and how can we best care for their conservation. Collaboration between conservators is equally important, as textile seal wrappings are normally found in collections cared for by conservators with expertise in books, paper and parchment, but who might be less familiar with textiles. Recent efforts, such as the series of talks Textiles in Libraries organised by conservators from the Bodleian Library, are helping to bridge this gap and to build professional networks.
Fig. 2 Lucía taking images with the digital microscope of the seal cord attached to a charter issued by King Henry III in 1227. London Metropolitan Archives, COL/CH/01/013.
Jitske: Speaking of connections, when I shared our blog on LinkedIn with my Dutch network I got some cool responses. Ed van der Vlist, curator of medieval manuscripts at the Royal Library in The Hague, presented some really intriguing wrappings made of flax fibres (Fig. 3). They look much like bird nests, which are basically bags for eggs. It would be absolutely exciting to experience the opening of the flax wrappers. And another colleague saw a connection with medieval textile relic purses. In our project team we’d also made this connection and it is definitely worth exploring further. Lucía, I think you agree how much can be gained when we go beyond the boundaries of our own discipline and exchange methods and ideas!
Fig. 3 Confirmation of income donated to the monastery of Engelendaal at Leiderdorp (the Netherlands), 1409-1478. Erfgoed Leiden en Omstreken, archief Kloosters van Leiden e.o. 0503 Inventaris van de archieven van de kloosters, (1310) 1393-1572 (1655), III.A.3.2, inv. no. 603.
This project was funded by the TNA’s Strategic Research Fund 2022-2023 (ref. 514 – SRF project “Out of the Bag”). We are grateful for the expertise provided by Paul Dryburgh, Elizabeth New, Ana Cabrera and Frances Pritchard.