Analysis of ancient DNA and RNA of human remains from different sites and time periods to determine the presence of viruses, but also bacteria and parasites. The aim is to get an overview of common pathogens (and perhaps microbiomes) at specific time points and to study past epidemics. 1. Northern Project : samples from northern Europe (Sigtuna, Westerhus, Frösön, Sandby borg) from the Iron and Viking Ages. 2. Iberian muslims : samples from an islamic medieval cemetery. Aim:look for smallpox DNA maybe brought from the Umayyad expansion. 3. Battles of Öland (Kronan flagship, 1676) and Wagram (1809) : Soldiers recent battles. Aim: look for preserved RNA and overview of common sicknesses of soldiers in campaign. 4. Helgeandsholmens (medieval Stockholm) and the mass grave of Korsbetningen (Battle of Visby, Gotland 1361) : Aim: look for even older RNA. 5. Plague of Athens 430BCE : described symptoms could be caused by smallpox more than the plague.