Today In History with The Retrospectors What Caused The Black Death?
Mar 20, 2026
They unpack medieval explanations for the plague, from planetary alignments to aerial spirits and folk cures. The conversation covers scientific causes like Yersinia pestis, flea and rat transmission, and shipborne spread. They explore persecution, Papal intervention, and migratory shifts. A surprising thread traces possible origins back to Mongolia and wartime contagion tactics.
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Stars Over Science Explained The Pestilence
- Medieval scholars blamed a rare triple planetary conjunction for the Black Death rather than microbes.
- The University of Paris' Compendium d'Epidemia argued Saturn, Jupiter and Mars in Aquarius produced humid, corrupt air that caused pestilence.
Bacteria And Trade Routes Fueled Rapid Spread
- Modern science identifies Yersinia pestis spread by fleas on rats and via respiratory transmission as the Black Death cause.
- Fleas and rats thrived on trading ships, explaining rapid port-to-port spread across medieval Europe.
Persecution Reshaped European Demographics
- Persecution targeted marginalized groups as explanations for the plague, driving violence and migration.
- Pogroms against Jews prompted papal intervention and large Jewish migration to Poland, reshaping European demographics.