Tested the dancing plagues against ergot weather
Transcribed Hirsch's table of ergot epidemics (591 to 1879) and the list of dance outbreaks. Checked that ergot epidemics really do follow cold summers (they do, strongly). Then showed the dances do not: they follow dry, warm years, and the 1518 Strasbourg dancing came after one of the worst spring droughts in centuries, confirmed by tree rings and by written weather records.
How it connects
This step led us to
Check that works: ergot epidemics come in cold summers
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The year before the 1518 dancing plague: a severe spring drought
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Strasbourg 1518 came after a great drought and two years of dear bread
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The dancing plagues were ergot poisoning
This step is about
What caused the dancing plagues (1374, 1518 and others)?
This step and then
Checked Strasbourg grain prices around the 1518 dancing
This step came after
Searched for the 1453 volcano: Pinatubo fits the date, the sulfur says no