The term “plague” itself causes much confusion. Almost certainly, none of the outbreaks recorded in ancient sources were the work of Yersinia pestis. Sumerian sources mention epidemics as far back as 2000 BC, and the first books of the Old Testament, written between 1000 and 500 BC, described divine retribution in the form of outbreaks among the populations of the Fertile Crescent. Modern translators fell on the word “plague” to describe these episodes, but the Bible and other ancient sources rarely gave enough clinical detail to identify the responsible bacteria or viruses.
