Researchers find earliest confirmed case of smallpox

Variola virus DNA found in bones of people from Denmark to Russia around Viking era

The Vikings are known for their intrepid seafaring, fearsome fighting and extensive trading, but it seems it may not only have been goods and weapons they carried on their travels - they could also have carried a deadly disease.

Researchers say they have found the world's earliest confirmed case of smallpox, revealing the disease was widespread across northern Europe during the Viking age.