Category Archives: Disciplines

Rats cannot have been intermediate hosts for Yersinia pestis during medieval plague epidemics in Northern Europe

Journal of Archaeological Science

Volume 40, Issue 4, April 2013, Pages 1752–1759

Rats cannot have been intermediate hosts for Yersinia pestis during medieval plague epidemics in Northern Europe

  • a University Museum of Bergen, University of Bergen, Norway
  • b Department of Physiology, Institute of Basic Medical Sciences, University of Oslo, P.O. Box 1103 Blindern, N-0317 Oslo, Norway


The commonly accepted understanding of modern human plague epidemics has been that plague is a disease of rodents that is transmitted to humans from black rats, with rat fleas as vectors. Historians have assumed that this transmission model is also valid for the Black Death and later medieval plague epidemics in Europe. Here we examine information on the geographical distribution and population density of the black rat (Rattus rattus) in Norway and other Nordic countries in medieval times. The study is based on older zoological literature and on bone samples from archaeological excavations. Only a few of the archaeological finds from medieval harbour towns in Norway contain rat bones. There are no finds of black rats from the many archaeological excavations in rural areas or from the inland town of Hamar. These results show that it is extremely unlikely that rats accounted for the spread of plague to rural areas in Norway. Archaeological evidence from other Nordic countries indicates that rats were uncommon there too, and were therefore unlikely to be responsible for the dissemination of human plague. We hypothesize that the mode of transmission during the historical plague epidemics was from human to human via an insect ectoparasite vector.

Effects of 1342 rainfalls at the Neckar river, southwest Germany

Written, archaeological, and geographical sources show the heavy effects of the rainfalls in summer 1342. The mostly refer to the river Main, the middle Rhine, Elbe, and Weser.  A charter from the town of Esslingen situated at the river Neckar, dated 9th of September 1342 documents a court ruling. The local Augustinian monastery sued  against Kaisheim abbey, which owned a nearby vineyard. Soil was flooded into the Augustinian monastery. The document shows that the rainfalls in summer 1342 also affected the Neckar valley.



The town of Esslingen depicted by Andreas Kieser. The wineyard ist situated below the castle
(HStA Stuttgart H 107/15 Bd 7 Bl. 22, via Wikimedia Commons)


Rainer Schreg

archaeologist professor in medieval and postmedieval archaeology at Bamberg university

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Late medieval apotropaic devices

The refers to a Master thesis from the University of Louisville dealing with c.

  • Lena Mackenzie Gimbel, Bawdy badges and the Black Death: late medieval apotropaic devices against the spread of the plague. MA thesis (Louisville 2010) – pdf from Louisville university.

Rainer Schreg

archaeologist professor in medieval and postmedieval archaeology at Bamberg university

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Introduction – Ted Boronovskis


I am an independent researcher from Perth, Australia who is interested in an as yet unexplained occurrence in the epidemiology of the Bubonic Plague – its apparent disappearance from Western Europe and the Medditeranian basin between AD750  until its reappearance in AD1347, whilst successive waves of epidemics continued in Central Asia and China.

The attached note was published in the medical history newsletter of the Australian & New Zealand society of the History of Medicine (4th series, No 38; Oct. 2012)




Molecular Traces of the Black Death

Over the last decade a substantial amount of molecular evidence confirming the etiology of the plague over virtually the entire medieval period has been produced. In this rapidly evolving field, evidence for the Black Death of the 14th century has been produced by each new method in turn.

Given the conditions of remains sampled to date, the methods fall into two main categories: genomics and immunology. There are pros and cons to each. Genomics has well-recognized specificity and the ability to compare with living and ancient strains, but non-nucleic acid methods are both specific and far more sensitive. Non-nucleic acid methods (using immunology) will give a better indication of the true incidence within a population, especially important when testing moves beyond mass graves. Immunologic methods have been the primary means of diagnosing clinical infectious disease for at least 30 years. The Rapid Diagnostic Test (RDT) now used to diagnose ancient and modern plague uses technology that has existed for over 25 years with a good track record. The downside of immunology is that it doesn’t give strain specific information. On the other hand, detection of degraded DNA much less getting good enough sequence for strain matching is difficult and inefficient.

This map charts all of the medieval plague molecular data that I have seen (view Plague Map in a larger map). The red balloons mark 6th-9th century, Plague of Justinian, sites. All three early medieval sites are beyond the Alps proving that the plague of Justinian penetrated well beyond the Mediterranean basin.  The yellow balloons represent 14th century data, with the starred balloon specifically dated to the first wave of the Black Death pandemic. The blue balloons represent post-14 century data (14th-17th century). Click the balloons for references.

Even a cursory look at the map makes it apparent that both pandemics reached beyond the Alps into the European plain. Further, the distribution represents the areas of activity of 3-4 research groups rather than as an indication of plague incidence across Europe. Every region so far examined and published has found some evidence of plague. There is both DNA and immunological evidence for the 14th century. Unfortunately, DNA data has been produced by three different groups who have not yet produced a consensus sequence or analyzed their differences. Despite the differences between their sequences, there is plenty of homology between their data and modern reference sequences to ensure that they all identified Yersinia pestis. Their differences are most likely to be primarily related to interpretations of degradative changes in the ancient DNA, though it is possible that more than one strain was active in 14th century Europe.

The map also makes it apparent that we only have molecular evidence from a very small sliver of the territory covered by the medieval pandemics. There are too few sites so far to make any predictions about the routes the plague traveled based on molecular evidence. It never travels from point A to point B as the crow flies! Plague spreads more like a spiderweb than a wave. So, long distance transmission may well exist before lateral spread fills in the countryside. It is absolutely necessary to take in consideration medieval trade and communication routes.

This is an exciting time to be working on the plague. So far, only the tip of the iceberg has been exposed. To date, the molecular evidence has been the most useful for confirming the etiology of the plague of Justinian, the Black Death pandemic, and plague’s endurance in western Europe. We have the technology now to map the geographic extent of Yersinia pestis for the first and second pandemic. It will take at least a generation of work from archaeologists, geneticists, and paleomicrobiologists to gather enough sites and resolve the fine-detail sequencing issues to begin to do strain mapping.


Medieval pig management

I have a new paper published that explores the impact of Black Death on pig management…I hope it is of interest.
Hamilton, J. and Thomas, R. 2012. Pannage, pulses and pigs: isotopic and zooarchaeological evidence for changing pig management practices in 14th century England. Journal of Medieval Archaeology 56: 235-260.
Zooarchaeological analysis of a substantial assemblage of animal bones excavated from Dudley Castle, West Midlands, suggests that a significant change in pig management occurred during the 14th century. A dramatic decrease in the relative abundance of pigs, combined with an increase in the size of post-cranial bones and teeth, and a higher proportion of neonatal individuals, raises the possibility that greater control over breeding and feeding was being exerted in this period through the emergence of enclosed husbandry practices. Carbon and nitrogen stable-isotope analysis of a sample of 41 pig mandibles from two tightly dated phases of occupation supports this interpretation. Between the late 13th century and later 14th century there was a statistically significant decrease in δ 15N, but not in δ 13C, and pig dietary diversity probably also decreased. This paper discusses several explanations for these patterns, all consistent with a major change in pig management at this time.

Justin Stearns – Contagion in Muslim and Christian Thought

I am assistant professor at New York University – Abu Dhabi. My interest in the Black Death is primarily Muslim and Christian intellectual and social responses to the plague. I have written a book comparing Muslim and Christian understandings of contagion in Iberia(, as well as a short review article on religious responses to the plague
( and continue to work on the plague in the Muslim world.


My interest in the Black Death is primarily Muslim and Christian intellectual and social responses to the plague. I have written a book comparing Muslim and Christian understandings of contagion in Iberia(, as well as a short review article on religious responses to the plague ( and continue to work on the plague in the Muslim world.

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Prof. Jan Esper

The 14th century has been identified as a period of global reorganization of climate. Links between major climate changes and widespread disease as well as cultural changes have been proposed. I am interested in the analysis of these climate shifts as well as the association with societal changes and impact.

Geographisches Institut, Johannes Gutenberg Universität Mainz

Julia Gamble – Bioarchaeologist

I am a doctoral candidate based at the University of Manitoba, Canada.

I am currently undertaking the final stages of my doctoral research investigating patterns of health in two Danish cemetery populations dated from the mid-14th to the mid-16th centuries. This project has a number of facets. It involves a complete skeletal analysis of a sample of 167 individuals from these populations to identify age, sex, and other health dimensions (ex, stature and pathology). Through this, I am interested in changes in health across the period, particularly at the point bordering the mid-14th century. I am also considering the relationship between the two populations, one being rural and one being urban. Finally, I am conducting histological analysis of teeth from these individuals in order to on one level gain insight into the patterns of stress during development over time and on another level to consider the relationship between childhood stress and adult health.

My approach is bioarchaeological in nature – I am interested in looking at human health through the study of skeletal remains, but in the context of the socioeconomic and environmental context of the mid-14th century crises.

Richard Thomas – zooarchaeologist

My interests in the impact of the Black Death and the 14th-century crises on animal husbandry, diet, and human-animal relations in general, stemmed from my doctoral research (completed in 2002). This research involved the analysis of a large assemblage of animal bones from a castle site located in central England (Dudley Castle), with material dating from the 11th to the mid-18th century. This analysis revealed some major changes in animal exploitation, most especially in the 14th century. Firstly it was apparent that a statistically-significant increase in the size of domestic livestock (cattle, sheep, pig, chicken) occurred in the later 14th century. Other notable changes in this period included increased consumption of wild birds, and altered hunting strategies as the aristocracy sought to maintain social boundaries in the face of social climbers. I have argued that each of these phenomeon reflects socio-economic and environmental consequences of the Black Death (and prior crises of the 14th century). These arguments are laid out in the following publications:

Thomas, R. 2005. Animals, Economy and Status: The Integration of Zooarchaeological and Historical Evidence in the Study of Dudley Castle, West Midlands (c.1100-1750). British Archaeological Reports British Series 392. Archaeopress,Oxford.

Thomas, R. 2005c. Zooarchaeology, improvement and the British Agricultural Revolution. International Journal of Historical Archaeology 9 (2): 71-88.

Thomas, R. 2006. Of books and bones: the integration of historical and zooarchaeological evidence in the study of medieval animal husbandry, pp. 17-26, in Maltby, M. (ed.), Integrating Zooarchaeology. Oxbow,Oxford.

Thomas, R. 2007. Maintaining social boundaries through the consumption of food in medieval England, pp. 130-151, in Twiss, K. (ed.), The Archaeology of Food and Identity. Center for Archaeological Investigations Occasional Publication No. 34,Carbondale.

Thomas, R. 2007. Chasing the ideal? Ritualism, pragmatism and the later medieval hunt, pp. 125-148, in Pluskowski, A. (ed.), Breaking and Shaping Beastly Bodies: Animals as Material Culture in the Middle Ages. Oxbow, Oxford.

More recently, I have begun to further develop some of these ideas. Analysis of pathology in the lower limb bones of cattle, has demonstrated that the cattle of the later 14th-century were being worked much harder than they were in the late-13th-early-14th century and in later periods. Perhaps this was a consequence of the increased demand on cattle for traction following the losses of the cattle panzootic, which resulted in a loss of 62% of cattle in manors in England (Slavin, P., in press. The great bovine pestilence and its economic and environmental consequences in England and Wales, 1310-50, Economic History Review):

Thomas, R. 2008b. Diachronic trends in lower limb pathologies in later medieval and post-medieval cattle from Britain, pp. 187-201, in Grupe, G., McGlynn, G. and Peters, J. (eds.), Limping Together Through the Ages: Joint Afflictions and Bone Infections. Documenta Archaeobiologiae 6: 187-201.

Stable isotope analysis of large samples of cattle and pig bones, is also beginning to support the view that animal diet and management was altered in the aftermath of the Black Death:

Fisher, A. and Thomas, R. in press. Isotopic and zooarchaeological investigation of later medieval and post-medieval cattle husbandry at Dudley Castle, West Midlands. Environmental Archaeology 17 (2)

Hamilton, J. and Thomas, R. in press. Pannage, pulses and pigs: isotopic and zooarchaeological evidence for changing pig management practices in 14th-century England. Journal of Medieval Archaeology 56: 235-260.

Such studies also question the reliability of assuming that stable isotope values in animals are unchanging. This is a critically important consderation for making interepretative sense of isotope values in human skeletal remains.

Most recently I have been involved in a City of London Archaeological Trust funded project which has revealed further evidence for increases in livestock size in the 14th century. When the Dudley Castle data were first published, there were no comparatively early medieval sites in England at which size change in livestock had occurred; the majority of other sites had shown increases one or two centuries later. This  project, undertaken by myself in collaboration with Dr. Matilda Holmes (University of Leicester), and Dr. Jim Morris (Museum of London Archaeology/University of Central Lancashire), has involved a systematic temporal and spatial analysis of archived measurements of cattle, sheep, pig and domestic fowl bones from archaeological sites in London from sites dating 1200-1900. We are currently just writing up the results, but key findings include two phases of size increase in the 14th century, which may well be connected to the impact of the sheep and cattle plagues of the first quarter of the century and an altered agricultural and tenurial landscape in the wake of the Black Death.

Ptolemaios Paxinos – zooarchaeologist

Polemaios-Dimitrios Paxinos (Institut für Paläoanatomie und Geschichte der Tiermedizin, Ludwig-Maximilians-Universität München, Germany).

Doctoral candidate of the Graduate Program of the ArchaeoBioCenter at the Ludwigs-Maximilian-Universität. Dissertation Topic: „Die Archäozoologie der Pest. Die Auswirkungen des Schwarzen Todes (1347-1350) auf Viehhaltung, Wirtschaft und Handel in Deutschland“ (The zooarchaeology of the plague: the impact of the Black Death (1347–1350) on animal husbandry, economy and trade in Germany).

The 14th c.  is from a zooarchaeological point view an exciting period since it is not known how the Black Death (as well as the other crises) affected domestic livestock. In order to understand its impact one must also bear in mind that the Black Death appeared after other crises already trembled several regions of the medieval Europe. Crises like the Great Famine or Bovine Pestilence affected dramatically the European population in many ways. Nevertheless, it seems that the Black Death has a special status within all the late medieval crises since it exacerbated and accelerated the already occurring changes, being some sort of catalyst.

In Germany the historic studies on the socio-economic consequences of the Black Death didn’t actually gain popularity till the 1980s. Hitherto, the German scholars published many studies on the Black Death, some of them being more compilations of the infected localities and relevant written sources, whereas others focus on the research of a certain region. Although those studies are important and some of the early works from the 19th c. are still the base for further research, they are dealing only marginally with economic and social impacts, which could be determined from a zooarchaeological point of view.

Since the Black Death was a pan-European phenomenon, multi-regional studies must be possible. In order to do that, a convenient database must be available. As for Germany, such a database doesn’t exist. Therefore it is necessary to create one which contains suitable zooarchaeological data. But one must pay caution because studies on a large scale have many difficulties; for example: a) the different state of research in different parts of Europe; b) the different context of findings (e.g. cloister, castle, village, town), which has an impact on the taphonomic interpretation; c) the excavation methods which differ from site to site; and d) the different standards of the published zooarchaeological papers. On top of that there is also the problem of dating and clear stratification.

To solve those problems a series of criteria which consider archaeological as well as zooarchaeological parameters must be chosen. Essential for the study is undoubtedly the dating of the sites coming into question. The most qualified are the sites which cover at least 50 or 100 years before as well as after 1350, i.e. they cover steadily the period 1250/1300–1400/1450.  Other criteria can be for example:

a) A suitable NISP (Number of Identified SPecimens) since an insufficient number of bones (e.g. less than 200) could disrupt the statistical evaluations.

b) In every study the respectively bone measurements bones must have been published, otherwise possible changes on the size of the domestic livestock (dicrease/increase) cannot be traced.

The idea behind this study is to detect any trends, be it a change of the animal size or a change of the proportion of species, among others. Such trends could point at modifications of living standards, terms-of-trade and agricultural practices. So far it seems that the response to the impact differed from region to region in Germany, hence detailed regional analyses are advisable.

Ptolemaios Paxinos

Doctoral candidate of the Graduate Program of the ArchaeoBioCenter at the Ludwigs-Maximilian-Universität. Dissertation Topic: „Die Archäozoologie der Pest. Die Auswirkungen des Schwarzen Todes (1347-1350) auf Viehhaltung, Wirtschaft und Handel in Deutschland“

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Human skeletal health before and after the Black Death

Ongoing analysis of the human skeletal remains from London by Sharon DeWitte reveals changes in health and lifespan in the wake of the Black Death, and adds to the growing body of bioarchaeological evidence that life for survivors was better.

Rainer Schreg

archaeologist professor in medieval and postmedieval archaeology at Bamberg university

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Yersinia pestis – the missing ecological and historical dimension

Reposted from

Yersinia pestis, Direct Fluorescent Antibody Stain (DFA),
200x Magnification
(Centers for Disease Control and Prevention‘s
Public Health Image Library [PHIL],
identification number #1918 [public domain]).
In a recent article a group of German and Canadian researchers presented the genome of Yersinia pestis as it has been extracted from burials of the London East Smithfield burial ground dated to 1348/49 (Bos et al. 2011). This site has been excavated by the Museum of London after it has been localised in 1986 (Grainger et al. 2008).
The article aims at the reconstruction of the ancient genome of Yersinia pestis, as this promises implications for the understanding of infectious diseases, as “genomic data from ancient microbes may help to elucidate mechanisms of pathogen evolution and adaptation for emerging and re-emerging infections”.
The authors conclude:
1.) “Genetic architecture and phylogenetic analysis indicate that the ancient organism is ancestral to most extant strains and sits very close to the ancestral node of all Y. pestis commonly associated with human infection. Temporal estimates suggest that the Black Death of 1347–1351 was the main historical event responsible for the introduction and widespread dissemination of the ancestor to all currently circulating Y. pestis strains pathogenic to humans.” The classic Black Death was quite different from previous epidemics. The authors refer to the Justinian plague “popularly assumed to have resulted from the same pathogen: our temporal estimates imply that the pandemic was either caused by a Y. pestis variant that is distinct from all currently circulating strains commonly associated with human infections, or it was another disease altogether.”
2.) “Comparisons against modern genomes reveal no unique derived positions in the medieval organism, indicating that the perceived increased virulence of the disease during the Black Death may not have been due to bacterial phenotype. These findings support the notion that factors other than microbial genetics, such as environment, vector dynamics and host susceptibility, should be at the forefront of epidemiological discussions regarding emerging Y. pestis infections.”

Rainer Schreg

archaeologist professor in medieval and postmedieval archaeology at Bamberg university

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