New perspectives on smallpox outbreaks and migration during the Viking Age

The project comprises two parts. The first is a study of the impact on society of the spread of the smallpox virus during the Viking era in Scandinavia. The second study concerns the genome of the Viking era population and immigration to Scandinavia. Both studies are based on earlier aDNA studies.

2020 saw the publication of two separate aDNA studies in Science and Nature, co-authored by Helene Wilhelmson and Ingrid Gustin. The Science article demonstrated for the first time that an extinct variant of the smallpox virus was widespread in Scandinavia during the Viking Age. The article in Nature addressed the genome of the Viking-era population. 

The studies resulted in new, comprehensive and largely unexploited research material that can be used to study the life histories of individuals as well as societal development at local level during the early Iron Age.

The discovery that the smallpox virus was widespread in Scandinavia as long ago as the Viking era raises completely new questions as to the impact the epidemic had on local communities. Who were the carriers? How were their health and social status affected? Were smallpox sufferers treated differently than other people?

To answer these questions the researchers will be analyzing data and archeological material from burial sites in southern Scandinavia, a region with the highest concentration of smallpox victims in Europe during the Viking Age. This will enable the researchers to conduct long time studies into how communities responded to the spread of a viral disease that turned into a pandemic.

The second study relates to the mapping of the genome of the Viking-era population. It is clearly evident that a few areas, notably the Baltic island of Öland, had a very high proportion of non-local people of highly varied geographical origins. Were they all first-generation migrants? Did either sex predominate among the migrants? If so, why? What inferences can be drawn about the cultural affiliation of the individuals based on type of grave and objects buried with them? Is there covariance between cultural affiliation and origins that can be seen from the individuals’ aDNA? 

It has been difficult to identify the individuals who migrated to Scandinavia during the Viking Age, so little is known about these people. The study will potentially contribute to research into the migration that took place during the Viking Age. This will in turn add detail to our knowledge of that era.

To answer the questions raised in the two studies, the researchers will let selected aDNA results interact with data from other kinds of analysis, such as isotopes, which reveal diet and migration, C-14 dating, and also with the results from analyses of graves and individual biographies based on osteological analyses of skeletons.