A fascinating article and topic for study! Sir Thomas Malory, in his Le Morte d'Arthur, writes of the quest and describes the knights venturing into a wasteland that is thought, by some modern scholars, to be referencing parts of Britain where a 6th century plague destroyed whole communities. Those passages were portrayed in the movie Excalibur by scenes of knights hanging from trees in a dark, forbidding forest, and where some of the questing knights perished.
Scientific studies are beginning to to bring meaning to literature and confirm what's long been suspected. There was a sixth century plague that brought death and destruction to Europe, including Britain, and it also helped lay low the floundering Roman Empire. FWIW
In 541 AD, eight centuries before the Black Death, a deadly infectious disease hit the Byzantine Empire, reaching Constantinople in 542 and North Africa, Italy, Spain, and the French-German border by winter 543 [1]. The so called “Plague of Justinian”, named after the contemporaneous emperor, led to mass mortality in Europe similar to that of the Black Death. It persisted in the territory of the Roman Empire until the middle of the 8th century and likely contributed to its decline, shaping the end of antiquity [1]. Based on historical records, this disease has been diagnosed as bubonic plague although discrepancies between historical sources and the progression of Y. pestis infections have led some authors to suppose that the Plague of Justinian was caused by a different pathogen (as discussed in [2]). This vivacious discussion was recently reinforced by an ancient DNA study of the second pandemic that also questioned whether Y. pestis was truly the causative agent of the first pandemic [3], [4].
MORE AT:
http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003349