John Kelly · 2005

The Great Mortality

An Intimate History of the Black Death, the Most Devastating Plague of All Time

Rough AI truth score

75/100

The book is right about the pathogen and extraordinary mortality. Its broad European fraction is plausible but uneven, while its older origin-and-route narrative predates decisive Central Asian ancient-DNA evidence.

Based on three central claims · medium-high confidence

The three claims

01Supported

The fourteenth-century Black Death was caused by the bacterium Yersinia pestis.

Independent ancient-DNA and protein studies have recovered Y. pestis from Black Death burials across Europe and reconstructed medieval genomes. That evidence resolves the older debate over alternative pathogens while leaving transmission ecology contested.

Distinct Clones of Yersinia pestis Caused the Black Death Nature: Source of the Black Death in central Eurasia

02Mostly supported

The Black Death killed roughly one-third or more of Europe's population within a few years.

Documentary, archaeological, and environmental evidence supports catastrophic continental mortality, with many regions losing a third or more. New pollen work shows pronounced spatial heterogeneity, so a single Europe-wide fraction conceals spared and devastated areas.

Nature Ecology & Evolution: Black Death mortality heterogeneity Cambridge: The Great Pestilence

03Mixed

The pandemic began far to the east and reached Europe through a simple Mongol siege-and-trade chain from China.

Trade and maritime routes from the Black Sea clearly mattered to European arrival, but recent genomes place a pivotal 1338–39 outbreak near Lake Issyk-Kul in the Tian Shan. They do not establish the book's longer, linear China-to-Caffa narrative.

Nature: Source of the Black Death in central Eurasia PNAS: Origins of European plagues after the Black Death

Other claims worth checking

Religious persecution turned Jewish communities into scapegoats despite their shared vulnerability.
Labor scarcity strengthened some survivors' bargaining power but did not produce one uniform social outcome.

What this number means. It is an AI-generated first-pass judgment of three central factual or causal claims—not a rating, exhaustive fact-check, or human peer review. Claim credits are 100% for supported, 75% for mostly supported, 50% for mixed, and 25% for weak, then averaged and rounded. Lower confidence means the score should move more as better evidence arrives.

Method three-central-claims/0.1.0 · checked 2026-09-01 · 3/3 selected claims assessed · method and source audit