The period from about 1000 to about 1300 saw a warmer-than-usual climate in Europe, which underlay all the changes and vitality of the High Middle Ages. Around 1300, however, the climate changed for the worse, becoming colder and wetter. Historical geographers refer to the period from 1300 to 1450 as a “little ice age.”

Across Europe, an unusual number of storms brought torrential rains, ruining the crops on which people and animals almost everywhere depended. Long-distance transportation of food was expensive and difficult, so most urban areas depended on areas no more than a day’s journey away for grain, produce, and meat. Poor harvests led to scarcity and starvation. Almost all of northern Europe suffered a Great Famine in the years 1315 to 1322.

Even in non-famine years, the cost of grain, livestock, and dairy products rose sharply, in part because diseases hit cattle and sheep. Increasing prices meant that fewer people could afford to buy food. Reduced caloric intake meant increased susceptibility to disease. Workers on reduced diets had less energy, which meant lower productivity, lower output, and higher grain prices.