The vikings had smallpox

In July 2020 we published a paper in Science on ancient smallpox viruses: Diverse variola virus (smallpox) strains were widespread in northern Europe in the Viking Age. That was a couple of years of work.

There were some write-ups, e.g. Viking Age Smallpox Complicates Story of Viral Evolution.

The paper was written in collaboration with Eske Willerslev and his GeoGenetics group in Copenhagen.