The life of a book holds many stories, all leaving an invisible signature trapped in the pages, waiting to be read by those with the keenest eye. However, what if an eye is not enough? Invisible traces have seemed impossible to recover, but this is all changing with recent technological advances available to us. The emerging field of Biocodicology¹ offers the tantalising prospect to read these long forgotten biographies, revealing complex stories of use, handling, storage and production.

But why is this relevant? What can we really learn that cannot already be ascertained from reading the text? The value of the materiality of manuscript production cannot be overstated. Understanding the craftsmanship involved in the production of materials, so intrinsically linked to the users themselves, are as much a part of the codex as the words inscribed on the page. Understanding book production in terms of the livestock economies that sustained them, the choice of animals (age, sex, breed), the idocincracies of each skin requiring specialist knowledge of treatment and production. But then there are additional stories imprinted on the completed text, how was it being used? Were these objects of reverence with barely a scratch as proof of their sacred status, or are they everyday books to be used and thumbed and splashed and cleaned? Much the same way as our favourite recipe books contain evidence of the ingredients we use, manuscripts may present similar signatures from their users, a drop of wine here, a stain of milk there, a veritable feast of biomolecules preserved for posterity, lying dormant waiting to be revealed.

Where were these books kept? In pristine condition in a specialist box away from the light and water and dirt that might transform them? Or were they accidental victims of severe weather conditions, flood or fires? All these situations can leave traces behind that we can now explore.

And what of the creatures living on the leaves? Bacteria and fungi are as much a part of the story as anything else, and can give us clues as to the storage environments of these objects, in addition to offering us the possibility of early diagnosis of detrimental strains that may need to be considered by the conservation teams.

These are some of the questions we are beginning to ask and trying to answer in the field of biocodiciology. Encompassing genetic, proteomic and lipid analysis, all these biomolecules are now accessible to us in a way that they never were before, and they are shining a light on some of the questions we perhaps thought could never be answered.

However, we would like to present biocodicology not just as new scientific techniques to be applied to cultural heritage objects, but rather as a true multidisciplinary field, needing the relevant expertise from manuscript scholars, scientists, conservators, digital analysts and crafter practitioners. It is a constant dialogue between the fields of what is wanted, what is needed and what is possible, each informing the others and enhancing their potential in ways that would otherwise not have been thought possible.

Biocodicology offers the possibility of conducting research in a way that compliments and integrates with the current methodologies, expanding the potential questions that can be answered. Using these techniques we have addressed a long held debate regarding the materiality of 13th C pocket bibles ², explored the production history of the York Gospels ³ and participated in the complete 360 analysis of a 12th century glossed gospel of St Luke ⁴. All of these projects have required collaboration between scholars from many different disciplines to be able to resolve the questions originally posed.

Over the years, we have amassed a large amount of data, particularly relating to parchment species, with over 5000 separate samples being analysed. This is starting to reveal a geographic pattern of species choice that could prove very useful in questions of origin and provenance. We are continually fostering new collaborations to expand the field and the data we acquire, so that it becomes more relevant with each sample added.

Part of the reason we have been able to access so many documents is due to the non-invasive sampling technique we developed alongside book conservators, using triboelectric extraction. This involves using a pvc-eraser to lightly wipe the surface of the parchment, and from the small crumbs generated we are able to extract enough proteins and DNA for subsequent analysis.

Broadly, the main techniques that are used in biocodicology are:

1. Protein analysis: including Peptide Mass Fingerprinting (eZooMS) and proteomic analysis. This allow us determine the species of animal used to make the parchment, assess the quality of production (related to lime exposure) and analyse surface treatments and/or stains (deposits from plants, medicines, or human touch)
2. Genetic analysis: both animal and microbiome. This gives further detail about the animal source, such as sex and sometimes breed, and offers the possibility of broad geographic provenance. The microbiome can inform about the environment the object has been stored in and potentially diagnose problematic microorganisms present.
3. Visual analysis: including transmitted light photography and macro lens photography. This gives crucial information regarding the preparation of the parchment, the choice of animal, the method of production and possibly even evidence of breed (in the case of sheep due to the presence of hair follicles).
4. Lipid analysis: currently under development. Analysing the fats present in the parchment offers the possibility of looking at climate signals and possibly dating.
5. Craft practice and recreation: allows us to gain further insight into the production of parchment, recipes, choice of skins, etc based on the limited documentation that is available. Through trial and error using experimental recreation not only can we gain further understanding in the nuances of parchment making but we can also create control data sets for our analytical procedures.  

Beasts to Craft is an ERC funded advanced investigator grant, awarded to Professor Matthew Collins, that brings together a large group of scholars from different disciplines to develop and establish the field of Biocodicology. Although the project consists of a european network of participants, part of the team, including myself, are based in Cambridge at the McDonald Institute for Archaeological Research. A biochemist by training, I have spent the last eight years working on the protein analysis of parchment, and I will continue to carry out this facet of the project here in Cambridge. In addition to the protein analysis we also carry out the genetic analysis of parchment, headed by my colleague Dr Matthew Teasdale, originally a cattle geneticist but also having branched out into parchment analysis over the last eight years. We are always open to new collaborations so please do not hesitate to contact us if you have any questions or would like to discuss participating in our project.

Dr Sarah Fiddyment is a postdoctoral research associate on the ERC Beasts to Craft project based at the McDonald Institute for Archaeological Research, University of Cambridge.

This project has received funding from the European Union’s EU Framework Programme for Research and Innovation Horizon 2020 under Grant Agreement No. 787282. 

Further reading

1. Fiddyment, S. et al. So you want to do biocodicology? A field guide to the biological analysis of parchment. Heritage Science 7, 35 (2019).

2. Fiddyment, S. et al. Animal origin of 13th-century uterine vellum revealed using noninvasive peptide fingerprinting. Proc. Natl. Acad. Sci. U. S. A. 112, 15066–15071 (2015).

3. Teasdale, M. D. et al. The York Gospels: a 1000-year biological palimpsest. R Soc Open Sci 4, 170988 (2017).

4. Gibbons, A. Goats, bookworms, a monk’s kiss: Biologists reveal the hidden history of ancient gospels. Science (2017).