 The mean evolutionary rate of the whole genome was 3.3 × 10−4 substitutions/site/year (credibility interval 2.0–4.8).The Marburg strains had a mean root time of the most recent common ancestor of 177.9 years ago (95% highest posterior density 87–284) suggesting an origin in the mid 19th century.In contrast, the Ravn strains origin dated back to a mean 33.8 years ago (the early 1980s).The most probable location of the Marburg virus ancestor was Uganda whereas that of the RAVV ancestor was Kenya.