A project using conservation science and materials analysis of medieval silk seal bags within The National Archives collection is opening up new questions about global exchange and the hidden richness of the archival record. This work is part of an interdisciplinary collaboration with Dr Amanda Luyster (College of the Holy Cross, Worcester, USA), entitled Whose Past? An Exploration of Imported Patterned Silks in Medieval Britain. The project brings together an international group of scholars in art historical inquiry and heritage science to better understand imported patterned silks surviving in medieval British contexts.
Seal bags
Seal bags are small, often overlooked objects. Designed to protect wax seals, which authenticate legal documents, they are easy to miss amongst thousands of parchment records. Yet, many were made from precious silks, textiles already old and reused, some originally woven abroad that were regarded as valuable long after their creation.
Examples of silk seal bags attached to their documents within The National Archives collection. E 42/524 (left) and 42/534 (right). Photo credit: Katerina Williams.
Taking an interdisciplinary approach to these silks, we examine colourants, metal wrapped threads, and weaving structures, combining scientific analysis with close visual and iconographic study. This approach enables us to better characterise known seal bags but also encourages us to look more deeply at our collection as a whole.
It was through this deeper engagement and interdisciplinary approach, followed by many hours of searching through boxes of medieval documents, that we discovered previously unknown silk seal bags.
Examples of newly discovered silk seal bags in The National Archives collection. E 40/15679 (left), E 326/12500 (centre) and E 212/95/i (right). Photo credit: Katerina Williams.
A standout discovery
When Mallorie Francis, a conservation student on placement with us, opened one more of the hundreds of small envelopes, her eye was caught by the bright colour and sophisticated pattern of a previously unknown seal bag. This seal bag has emerged as one of the most striking discoveries of the project. It is part of E 40/15679, a record Discovery, The National Archives’ own catalogue, described as:
‘Confirmation by William de Monteforti, dean, and the chapter of St Paul’s, of the appropriation to Holy Trinity Priory, London, of the church of Broomfield, Essex. Date: 1292.’
On the surface, nothing in this description suggests that a luxury textile might accompany the document. The catalogue entry captures the legal and administrative act it records, precisely what The National Archives was designed to preserve, but it offers no indication of the material artefacts attached to it. And yet, associated with this document is a silk seal bag of extraordinary quality and significance.
Looking beyond the description
The silk is woven in red, yellow and green. It features complex, vibrant patterns, including roundels containing fantastic animals, framed by additional animal motifs, octagonal stars, and rosettes (E 40/15679). Even encountered today as a fragment, the visual and material impact of the textile is unmistakable.
Wide and close up images of E 40/15679. Bottom right image is from the inside of the silk seal bag. Photo credit: Katerina Williams.
Two of our team members, Silvia Saladrigas and Ana Cabrera Lafuente, quickly identified the piece. They determined that both technically and stylistically, this silk is closely related to a well-known medieval textile showing griffins, found in the tomb of Santa Librada at Sigüenza Cathedral, in the town of Sigüenza (a small village around 120 km from Madrid). Fragments of this fabric are preserved in a number of major museum collections, including New York’s Metropolitan Museum of Art, the Cleveland Museum of Art, the Terrassa Textile Museum, and the Museum of Fine Arts, Boston, among others (Figure 1). The Sigüenza textile is dated to the 12th century and associated with Islamic production in Spain (al-Andalus), within a broader Mediterranean luxury silk tradition connecting to North Africa and the Near East.
Figure 1. The closely related Sigüenza textile found in our collection (left) alongside 'Lampas with griffins in roundels, from the Reliquary of Saint Librada in Siguenza Cathedral' from The Cleveland Museum of Art (left). The blue rectangles highlight the matching areas.
The Cleveland Museum of Art, Purchase from the J. H. Wade Fund, 1952.152
At the same time, subtle differences in design distinguish the textile associated with E 40/15679 from the fragments from Sigüenza held in these collections. Small iconographical variations suggest that The National Archives fragment is a closely related fabric. It was likely produced within the same geographical region or by a closely connected workshop sharing comparable technical knowledge, materials, and aesthetic conventions. It is a significant discovery that casts new light onto a much-better-known textile held in international collections.
Its reuse as a seal bag for a late 13th-century English ecclesiastical document introduces a striking temporal and geographical layering: a silk already old and prestigious, repurposed to safeguard the authority of a legal act. That such a textile survives quietly within a record whose description makes no reference to silk, highlights the importance of interdisciplinary, object focused research to bring the full material histories of records to light.
Research threads
Scientific analysis and art historical comparison allow us to situate this silk within wide-ranging networks of production and exchange. The weaving, dyes and decorative language all point to a Mediterranean world in which al-Andalus (Islamic Spain) was a major centre of luxury textile manufacture. These technical features are illustrated in Figure 2, which presents comparative examples and photomicrographs (photographs of objects under a microscope). These images highlight the weaving structures, the use of coloured silks and metal thread components.
Figure 2. E 42/524 (left) and E 40/4913 (right). Alongside associated microphotographs showing weaving techniques, coloured and metal threads.
Analysis of the colourants (substances used to add or change the colour of the textile) also adds crucial perspective, as shown in the close-up digital photomicrographs in Figure 3. For the closely related Sigüenza textile found in our collection, E 40/15679, the red threads were identified as a mixture of kermes and madder, while the yellow was dyed using yellow larkspur. Kermes, derived from scale insects, was among the most costly and prestigious red dyes of the medieval period and was strongly associated with power and high status. Although its origins lie in the Mediterranean, kermes circulated widely and was used across Europe and parts of Asia for centuries, making it a key indicator of participation in long-distance trade and specialist dyeing traditions. Madder, more readily available, could be combined with kermes to intensify hue, adjust tone, or extend the use of this valuable resource.
Yellow larkspur, prized for its brightness, contributes to a palette that is both visually striking and materially elite. While not a dominant dye source in medieval Europe, larkspur is well documented in textile production across Central Asia, Persia, and South Asia. Its presence here is consistent with the use of imported dyestuffs or dyed yarns within high-value silk weaving centres linked to eastern and Mediterranean trade networks.
Figure 3. Digital photomicrographs of colourful threads in four of the silk seal bags in The National Archives collection. Pictured samples are from E40/4913 (top left), E41/494 (top right), E42/524 (bottom left) and E42/529 (bottom right).
Taken together, the deliberate selection and combination of these dyes reflect a high level of technical knowledge, aesthetic intention and material investment. They support the interpretation of this silk as a product of established luxury textile traditions rather than local or ad hoc manufacture. The presence of kermes and larkspur within a textile associated with al-Andalus highlights the interconnected nature of medieval dye economies and the movement of materials, expertise and finished textiles between East and West.
Its survival at The National Archives reminds us that medieval Britain did not merely receive and create administrative objects such as documents and seals; it also absorbed and repurposed materials from around the world. These silks moved across cultures and contexts, shifting meaning as they went, from luxury cloth to reused fragment to an object safeguarding legal authority.
Looking again at Discovery
This work prompted reflection on how we encounter and understand archival collections.
‘Discovery’, our own catalogue, records what documents are about, their administrative purpose, their historical function and their place within legal and institutional histories. What it cannot always convey is the full complexity of the records themselves, or of the objects and materials that may accompany them.
Without close physical examination, the presence of a Spanish silk of such recognised importance alongside a record like E 40/15679 could easily remain unseen. The medieval silk seal bags project demonstrates how interdisciplinary research complements catalogue descriptions, enabling us to better understand the richness and diversity of the collections in our care.
In this case, a document described as a routine ecclesiastical confirmation also preserves material evidence of medieval Britain’s deep entanglement with Mediterranean luxury production, connections that are, quite literally, tied to the parchment.
What the archive holds
Discoveries like these challenge assumptions about what archives contain.
Catalogues exist to describe documents and their content, not their materiality or context, and yet material histories persist alongside the written word. By applying heritage science and interdisciplinary research methods, we can recover narratives that are otherwise easily overlooked.
The silk seal bags project has shown that even a vast, well-studied collection still holds surprises, objects waiting not so much to be found as to be recognised.
Members of the research team working on the project at The National Archives.
