The following is a brief summary/ link compendium on the previous relevant posts in this subreddit, taken from my previous posts in: Why are there not as many accounts of the bubonic plague from Asia compared to Europe if it is said to have started in Asia?
In short answer, the current academic consensus is that outbreak of pestilence(s) and other natural crisis like flood certainly contributed to the political instability in China that would lead to the retreat of the Mongols into Mongolia, but possibly related primary texts from Yuan China are not enough good to identify what kind of 'pestilence' really was (Cf. Crossley 2019: 160; Favereau 2021: 257-59).
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While there will always more to be discussed especially on this historical event even from a view of global history, the following posts respectively by /u/mikedash and myself are a kind of departure points to the further discussion:
In short:
- Eastern/ Chinese-Mongolian origin hypothesis of the Black Death has (had? - see below) still not accepted by nearly all of the historians, including Ole J. Benedictow, authority of the Black death study. Alternative place of origin is steppe areas in SE Russia, roughly based on some contemporary Russian chroniclers.
- Pre-Modern Chinese historical texts, especially its official history, is not so ideal source to explore which kind of disease(s) caused the outbreak. Yuan China also suffers from general dearth of the reliable contemporary account (We should wait for late Ming or even early Qing period to have a good amount of local historical gazettes - see also my previous post in :Primary sources for the Great Plague during the Ming dynasty).
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Books mentioned above:
- Crossley, Pamela K. Hammer and Anvil: Nomad Rulers at the Forge of the Modern World. Lanham: Rowan & Littlefield, 2019.
- Favereau, M. The Horde: How the Mongols Changed the World. New Haven: Yale UP, 2021.