Biologist Shai Carmi et al. demonstrated several years ago (in Nature Communications) that the entire contemporary community of Ashkenazic Jews, numbering very roughly ten million individuals, can trace its ancestry to an effective population of about 350 persons living in Poland at the midpoint of the Fourteenth Century. Historians have been slow to examine the powerful and deeply troubling
... [Show full abstract] implications of Carmi’s work, which invites exploration of how a once extensive population of Jews in the Roman Empire could have been almost completely extinguished during the Medieval era. This paper examines several possible historical hypotheses that have been put forth to explain Carmi’s so-far uncontested scientific finding, and concludes that the most powerful contributor to the decimation of the root population in the Roman Empire was likely to have been religious-inspired violence taking place during the lengthy period of the Crusades and immediately after the Black Plague epidemic.