<P> A study reported in 2011 of skeletons exhumed from the "Black Death" cemetery in East Smithfield London found Yersina Pestis DNA . An archeological dig in the vicinity of Thornton Abbey in Lincolnshire was reported in the science section of The Guardian for November 30, 2016 not only confirming evidence of the Yersina Pestis DNA in the human remains exhumed there but also dated them to mid-1349 . </P> <P> Genotyping showed that it was (at that time) a newly evolved strain, ancestor of all modern strains and proved the "Black Death" was bubonic plague . Modern medical knowledge suggests that because it was a new strain human immune system would have had little or no defense against it, which helps to explain its virulence and high death rates . </P> <P> The "Black Death" seems to have originated in Central Asia, where Yersina Pestis bacterium is endemic in the rodent population . It is unknown exactly what caused the outbreak, but a series of natural occurrences likely brought humans into contact with the infected rodents . The epidemic reached Constantinople in the late spring of 1347, through Genoese merchants trading in the Black Sea . From here it reached Sicily in October that same year, and by early 1348 it had spread all over the Italian mainland . It spread rapidly through France, and had reached as far north as Paris in June 1348 . Moving simultaneously westward, it arrived in the English province of Gascony around the same time . </P> <P> Grey Friars' Chronicle </P>

What devastating war began between england and france in the mid-1300's