Yersinia pestis
Historians are currently divided about the role of Y. pestis in the Black Death. Some historians said that the Black Death spread far too fast. Therefore, Y. pestis could not have caused it. DNA from Y. pestis has been found in the teeth of some of the victims of the Black Death. For this reason, Y. pestis must have been at least a factor in some (but not necessarily all) European plague epidemics.