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Okay, I've confirmed that the corrected text of the Marmot Supplement has been posted. So I will do a short thread summarizing key points from "The Four Black Deaths" (hereafter, 4BDs). A reminder that the essay+supplement are #OpenAccess until 12/31: https://academic.oup.com/ahr/advance-article/doi/10.1093/ahr/rhaa511/6040962. 1/n
tl;dr
1) the Black Death (= #2ndPlaguePandemic) started in 13thC not 14th
2) wasn't just Mediterranean/Europe
3) originated w/ spillover out of marmot reservoir of plague → Big Bang
4) likely spread thru Mongol Empire via grain supplies
5) we need a rethink of 13thC history 2/n
1) the Black Death (= #2ndPlaguePandemic) started in 13thC not 14th
2) wasn't just Mediterranean/Europe
3) originated w/ spillover out of marmot reservoir of plague → Big Bang
4) likely spread thru Mongol Empire via grain supplies
5) we need a rethink of 13thC history 2/n
OK, now for a slightly deeper dive. Why suggest that the Black Death had an earlier origin & wider footprint than we've suspected before? Genetics! Work in the past decade on #YersiniaPestis has transformed what we know about the history of this phenomenally lethal organism. 3/n
Here's fig 1 from 4BDs, now marked up (in orange) to show the geography of the different branches of the Y. pestis phylogenetic tree. As you can see, the European Black Death (documented from aDNA) is not the central "event." The Big Bang is. 4/n
So, now we know THAT something happened that historians had never suspected before. But WHEN & WHERE did it happen? Geneticists proposed a molecular clock dating of the Big Bang that would put it somewhere in the 2 centuries before the Black Death. But that's a big margin. 5/n
As for WHERE, that remained up in the air. So I did what we historians always do when we have an event of uncertain date: I looked for any indications that might constrain the possibilities. W/ so little aDNA that was pub'd, I looked at where the living descendants were. 6/n
That's what's in the Marmot Supplement (make sure you download this, too, before it slips behind the paywall: https://academic.oup.com/ahr/advance-article/doi/10.1093/ahr/rhaa511/6040962). Bob Hymes had already worked thru much of this data for his 2014 study on plague at the Mongol sieges of Song China: https://scholarworks.wmich.edu/tmg/vol1/iss1/12/ 7/n
But we assumed that, b/c those apparent plague events were so early, they must have been separate from *the* Black Death documented by western Eurasian sources. And then, I discovered Rashīd al-Dīn. (Shout-out here to @shahanSean who checked the Arabic original for me.) 8/n
I spent next 3 years trying to find any corroborating evidence for the westward spread of plague in the 13thC. And then it fell into my lap: Quṭb al-Dīn al-Shīrāzī's *Mongol News*, which not simply documented a plague-like event at Baghdad, but the crucial clue of millet. 9/n
The most crucial sentence is this: "My proposal is falsifiable, should aDNA demonstrate the presence of specific strains of Y. pestis at times or places that contradict the scenarios I have proposed." In the meantime, we all have a very modern pandemic to attend to. 10/end
