For the first time, scientists have reconstructed the ancient genomes of human betaherpesvirus 6A and 6B (HHV-6A/B) from archaeological human remains more than two millennia old. The study, led by the University of Vienna and University of Tartu (Estonia) and published in Science Advances, confirms that these viruses have been evolving with and within humans since at least the Iron Age. The findings trace the long history of HHV-6 integration into human chromosomes and suggest that HHV-6A lost this ability early on.