Overview
- Researchers from the University of Cambridge and GWZO report that ice-core sulfur spikes and Pyrenees tree-ring “blue rings” indicate a major eruption around 1345 that produced several cold, wet summers.
- Documentary records show Mediterranean harvest failures followed, prompting Venice, Genoa and Pisa to import grain from Golden Horde ports around the Black Sea.
- The authors argue that fleas infected with Yersinia pestis likely traveled with these grain shipments into Mediterranean ports, helping seed the 1347 outbreak.
- Cities dependent on grain imports were struck early and hard, while places that did not import after 1345, including Milan and Rome, largely escaped the initial wave.
- Published in Communications Earth & Environment, the work integrates climate proxies and historical data, complements 2022 genetic evidence pointing to a Central Asian reservoir, and emphasizes that the pathway remains plausible rather than proven.