A cooling in climate caused widespread crop failure in Europe in the early fourteenth century.
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While the climate had cooled somewhat, the immediate cause of the Great Famine of 1315-1317 was very heavy rains that flooded fields and destroyed crops in much of Europe in all three years. The following years were also very wet, and the recovery did not take place until 1322.
Crop Failure
in europe it was summer rains and bad weather
...thePlague or Black Death.
Black plague
The cut off contact with Japan A+
The cut off contact with Japan A+
It Resulted in crop failureFamine.
In the fourteenth century, the Black Death was plaguing Europe.
feudalism
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D. Competition among rival states
The fourteenth century in Europe did not differ demographically from the High Middle Ages much. The large-scale migration of peoples all over Europe had mostly happened between 400 and 800 AD . The later Viking migrations into England, Russia and Sicily had happened in the centuries thereafter, but by the 13th century big demographic shifts had become a thing of the past. The only very notable change was that the 14th century had seen the second Great Plague, also known as the Black Death, that killed between 50 and 70% of Europe's population.