Category Archives: natural disasters

CFP: Contagions sessions at the International Congress for Medieval Studies 2018

by Michelle Ziegler

Contagions: The Society for Historic Infectious Disease Studies has been given the opportunity of organizing three sessions at next year’s International Congress for Medieval Studies. This is the equivalent of a full day at the congress. The Congress will be held from May 10 to May 13, 2018, at Western Michigan University in Kalamazoo Michigan.  Our sessions next year will be:

Interdisciplinary Approaches to Historic Disease I and II

These two sessions are open to any aspect of study on infectious diseases and nutritional disorders in people and animals from the Late Antique to Late Medieval periods (400-1600 CE). These sessions are intended to be interdisciplinary as sessions, not necessarily as individual papers. Presentations on infectious diseases in literature, history, archaeology, and anthropology are all welcome.

Signs of Resilience in Medieval Populations

Major epidemics and natural disasters are ideal situations to study community resilience. No community is resistant to natural disasters; resilience is the best we can expect. Epidemics like the Black Death hit multiple communities in rapid succession but not all communities were equally affected in the short or long term. There are so many questions that can be asked.

  •  What allows some communities to quickly rebound while others dwindle away?
  • How do people mentally cope with a famine and/or massive epidemic?
  • What changes did communities make to better prepare or prevent a similar disaster in the future? Examples would include rebuilding flood walls or rerouting a river, increasing communal food stores, or building a surveillance system to detect the plague.
  • How did past experiences alter the community response to the next epidemic or another disaster?
  • How did responses differ between types of disaster (epidemic, flood, earthquake)? Flooding, at least, would be expected on a regular basis.
  • How did they prioritize their response? For example, did community leaders prioritize the economy (import/export) over public health?
  • What role did religious institutions play in disaster response?


Presentations are limited to 20 minutes. PowerPoint-like presentations are encouraged.  Participant Information Forms and an abstract are due to Michelle Ziegler by September 15th, contact prior to that date would be appreciated. Initial contact can be made through the form below.


Roundtable on Campbell’s Climate, Disease, and Society in the Late Medieval World

by Michelle Ziegler

Bruce Campbell. The Great Transition: Climate, Disease, and Society in the Late Medieval World. Cambridge University Press, 2016.


When I first learned that Bruce Campbell was working on this book, I wondered if it would be the first grand synthesis of the new paradigm. Although there have been some very good regional books in the last couple of years, Campbell has indeed brought forward the first analysis of the Black Death and 14th-century crisis using global evidence. Although not entirely clear from the publisher’s description, this is an economic history that draws on interdisciplinary evidence.

I proposed this session and recruited participants without ever seeing the book (though I had seen his Ellen McArthur Lectures). I got very lucky that the panel matched up so well with the book. The five panelists who were able to attend were (from left to right below) Mongolian historian Christopher Atwood, Historian of Medicine Wendy Turner, Evolutionary Biologist Boris Schmid, Archaeologist Carenza Lewis, and Economic/Environmental Historian Philip Slavin.

roundtable 2017
Great Transition Roundtable: Christopher Atwood, Wendy Turner, Boris Schmid, Carenza Lewis, and Phillip Slavin. (Photo by Nükhet Varlik, used with permission)

Everyone agreed that Campbell’s book will become the foundation upon which the new synthesis of plague history will be built. Campbell synthesized a vast amount of data with a particular appreciation for the integration of climate and disease data. Most agreed that this was a very high-level view of the crisis, an aerial view if you will, that leaves many details to be filled in. Some missed an analysis of the relationship with cascading levels of analysis down to the level of individuals. On the other hand, Atwood remarked that this is far more detailed than would be possible in Asian studies today. Perhaps not surprisingly, this interdisciplinary panel would have liked to see more evidence from other fields such as archaeology and social history used.  As Lewis noted, archaeology, in particular, could have given more support to the economic and environmental arguments without pulling away from the flow of the book.

The global evidence is primarily limited to climate data. Several panelists remarked that it is still very Eurocentric view, and Anglo-centric on top of that. There is more data that could have been gathered particularly from the Mediterranean. War as a syndemic factor and as a result of climate or disease weakened societies was not given much space in Campbell’s analysis. One effect of such a high-level regional treatment is that causes of local mortality from war (including the environmental destruction of war) can be overlooked because it doesn’t effect a large enough piece of territory. Slavin has also pointed out that Campbell’s interpretation tends to come across as somewhat deterministic, here and there. Thus, in discussing the Great European Famine of the early 14th century, Campbell provided an engaging analysis of the environmental context of the famine as its causation, without considering various intermediate links, demographic and institutional. As a result, Slavin noted that Campbell’s interpretation of the Great Famine as an exogenous disaster stands out as unilateral; famines, across space and time, are incredibly complex phenomena.

Developing a historical paradigm based heavily on scientific data is like building a house on shifting sand. Eventually, the sand will swallow the house. The best you can hope for is to be precariously perched on the ridge of a dune.  Most biological data is out of date by the time it is printed in a book. While there were a few misunderstandings, most of the discrepancies between Campbell’s portrait of the plague and other diseases is simply out of date even though he incorporates information up to about 2015. For example, ancient DNA studies have found evidence for at least one, and probably several, (still unlocated) local reservoirs of plague in or near Europe, so the idea that plague was frequently imported from the East no longer holds (but Boris disagrees on this view).

Some other hypotheses on plague transmission, though proposed several years ago, have failed to gain much traction. While evidence continues to mount that the soil plays a role in Yersinia pestis’ survival and that human ectoparasites could be the primary vector at the pandemic level, these hypotheses are not proven yet. This doesn’t mean that they won’t eventually be accepted, just that we are not yet there.

Figure 4.05 REV 6
Stages in the plague cycle (Figure 3.27, Campbell 2016)

I am reproducing figure 3.27 here because I think this will prove to be popular with teachers. With that being said there are a few comments that need to be made about it. The role of the soil in the enzootic environment of the rodent’s burrow is poorly understood at the moment. However, teachers could just explain that level 1 simply represents the environment of the rodent burrow.  Level 5 is where the real debates are going on now among those who study transmission. Campbell does leave open which ectoparasites are involved, human fleas or lice, but there is not yet general acceptance of human ectoparasites as major vectors. It may yet come, but we aren’t there yet. While local cases of pneumonic plague will occur any time there is bubonic plague, it is unlikely to be a major driver in a pandemic. The red box that I have added to the figure is where the really critical events are happening for human epidemics and pandemics. While I do believe that humans should be considered hosts in pandemic level transition, a variety of other hosts, always including rodents, will continue to be instrumental in the amplification and must be involved for the endurance of an outbreak in a locality.

While working with scientific detail is challenging for historians, after Campbell’s book I think it will be necessary to address scientific information at least to the level where there is a consensus. As long as historians stay with information that has been confirmed by a second study or that has obviously gained scientific consensus, the risks of using scientific information really are manageable. Finding a scientist who has your trust to comment on drafts is a good practice (and the reverse for scientists writing history!).

There were some concerns. There was a feeling that correlation does not necessarily equal causation. Schmid and Slavin would have liked to see more evidence of statistical analysis to support the conclusions drawn. They had a sense that the patterns that Campbell noted in a number of his overlapping time series might prove to be coincidental, rather than significant when tested with robust statistics.

Wendy Turner addressed pedological uses of the book. She found that, at least for a history of medicine course, it could not be used alone as a textbook. It does not have enough social history to address the complete impact of the Black Death. I don’t think that was its purpose, as much as some of us hoped it would be.  “The” Black Death book has yet to be written. When it is it will have to address all the social, medical, scientific, economic, and political impacts — a tall order. It is likely that aDNA studies will have more to contribute to shore up the transmission routes of such a project. Campbell’s book could be a major text (if not the only one) for an economic or environmental history course if it is supplemented by other texts. Archaeology as done by Carenza Lewis or Per Lagerås would support Campbell’s overall argument.  Turner and others agreed that it is not written for introductory students and they wondered how even upper-level students would respond to the density of the material. It should be required reading for graduate students who focus on the 14th century or any of the infectious/famine crises.

Atwood observed that historians tend to recognize a “crisis” about every couple of centuries and wondered if these mostly European events/crises over millennia were not tied to changes that had swept across all of Eurasia. In effect, Campbell’s book lays the supportive groundwork for arguing that the Eurasian land mass should be considered as a whole rather than European only or Asian only.  I think we could make an argument that the Afro-Eurasian landmass is one historic unit. The Indian Ocean is still an underappreciated communication avenue.

The most lively discussion with the audience concerned the terminology for the 14th-century events — transformation, crisis, collapse, etc. Positions seemed to be based at least partially on training, with some rejecting the term collapse under any circumstances, while others were more open to its use in areas like “population collapse”.  For me, this is an internal matter for historians to resolve. Terminology can be a fickle thing, but data is always preeminent. And that is a good place to leave this post. Campbell has done us all a service by compiling a huge amount of data that will be the foundation of a new era of analysis of the 14th century and the Black Death. For this above all else, we must be grateful.


Challenging Virgin Soil Epidemic Assumptions 

The depopulation of Native Americans during the 16th to 18th centuries, one result of the ‘Columbian Exchange’, has been held up as the ultimate example of virgin soil epidemics. The emphasis put on the ‘virginity’ of the native population, bordering on biological determinism, has absolved the colonial powers of a multitude of sins. Some archaeologists and historians of early North America have begun to challenge the emphasis placed on the virulence of the new pathogens in the native population without minimizing the depopulation itself. They have uncovered multiple additional factors that led to such a drastic loss of native Americans.

Chiaves la florida, 1584
Chiaves la florida, 1584

I recently finished Paul Kelton’s Epidemics and Enslavement: Biological Catastrophes in the Native Southeast, 1492-1715 (2007) and it was illuminating. He is covering the area of the modern Carolinas, Georgia, northern Florida, and Alabama and contiguous frontiers. This area was colonized by the Spanish, English and the French toward the Mississippi. These infant colonies set off an extensive reorganization of native tribes as trade goods shifted the balance of power throughout the region.

The colonial powers were initially interested in resource extraction over building large colonies. This region had only two easily exploitable resources — deer skins and slaves. This sparked a period of nearly constant intra-tribal warfare and the creation of confederations for protection.

Kelton shows that native depopulation did not occur solely due to epidemics, but due to a set of actions taken by the colonial powers primarily in Carolina. In the first century of the English colonies, native tribes became dependent upon trade good especially guns, powder and shot that were paid for with deer skins and captives. Moreover, the English wanted primarily women and children as captives. Eventually this led to a gender imbalance in most tribes preyed upon for captives. This made it nearly impossible for the tribes to recover from severe epidemics. Having enough women of reproductive age is absolutely necessary for population recovery after an epidemic or any other sudden population loss.

Kelton does not look at human genetic analyses but this makes me think of population analyses in Central and South America where native mtDNA lineages (via matrilineal only) are common but native Y chromosomes are very rare. Many female captives would become wives to immigrant men and their offspring are advantaged over all North American native children. Kelton never really explores the destination of native captives/slaves but implies that many went to markets outside of the English colonies. He implies that it was primarily when native captives were exhausted that Carolina turns to more African slaves.

As the tribes disintegrated from the stresses of warfare and slave raiding, they reorganized into the confederations we are more familiar with, like the Cherokee, Creeks, and Choctaw. None of the groups existed before the colonial period.  In the process of reformation many villages were abandoned. They resettled in a tighter configurations and some built palisades for the first time. In the past many of these settlements were claimed to have been depopulated by epidemics.

Natives in the south-east were primarily farmers who supplemented their diet with venison, fish and other salvaged sources of protein. Without domestic animals for protein, their nutrition was maintained by a precarious balance of crops liable to be disrupted by climate and social disruption. Evasion of slave raiding parties made it difficult to grow crops (most maize) and gather supplementary wild food (deer, fish, oysters, fruit/berries etc). Famine coupled with enteric disease has to be a significant factor in any explanation of native depopulation.  Even before 1492, native populations showed signs of nutritional stress and short lifespans, sometimes with average lifespans in the low twenties.

I’ve focused on non-epidemics causes of depopulation so far because this was the newest material to me. Kelton postulates that malaria was the first epidemic disease to spread among the native population. Malaria is likely to have become entrenched in wetlands early, but how quickly it spread is more questionable and he seems to minimize its demographic impact.  From my own research on the mid-Mississippi valley, malaria makes its first appearance in the records with the arrival of the English even though the French and Spanish had been in the valley long before.

Smallpox is generally considered the most dangerous pathogen of the Columbian Exchange. Kelton acknowledges that smallpox first came to the Spanish missions in Florida and Georgia, but asserts that these epidemics were limited to the mission system. Native North Americans did not have the population density or extensive trade networks found in Mexico and further south. He shows that smallpox (and perhaps measles) did not begin to spread between tribal groups at distance from the colonial settlements until the English facilitated native enslavement system, always done through native partners, developed. By the mid-18th century, native tribes stopped cooperating with the British to sell captives creating a more direct confrontation between the European colonies and all native groups, and increasing the importation of African slaves.

Supposed virgin soil epidemics have been an attractive explanation for demographic collapses in part because it comparatively simple, absolving humans of more responsibility. Humans are portrayed as being victims of biology. Finding other causes does not clear new pathogens of a significant role in native depopulation. Epidemics remain an integral piece of the puzzle, but only a piece.

Reference: Paul Kelton, Epidemics and Enslavement: Biological Catastrophe in the Native Southeast, 1492-1715. Lincoln & London: University of Nebraska Press, 2007.