THE THIRD HORSEMAN

Erudite rendering of the cataclysmic climate changes wrought at the start of the 14th century.

Rosen (The Most Powerful Idea in the World: A Story of Steam, Industry, and Invention, 2010, etc.) delights in the minutiae of history, down to the most fascinating footnotes. Here, the author delivers engrossing disquisitions on climate patterns and dynastic entanglements between England and Scotland (among others), and he posits that the decisive advent of cooler, wetter weather in the early 14th century signaled the beginning of the end of the medieval good times. Indeed, the preceding four centuries of the Medieval Warm Period, caused by all kinds of controversial factors such as the North Atlantic oscillation, produced temperatures several degrees warmer than average, which translated into a host of significant ramifications. A longer growing season and the ability to grow cereals (and wine) for the first time in higher altitudes in northern Europe meant more food for more mouths, encouraging a huge population explosion and need for the bursting of borders. While the years between 800 and 1200 had embedded the medieval institutions of manorialism and feudalism, which firmly “bound the laborer to the land, and the landlord to the laborer,” the warmer era had also encouraged the marauding Vikings to take advantage of melted polar ice caps to populate Greenland and move on to America and William the Conqueror to defeat the English at Hastings. By 1300, a crisis had been reached as new currents of nationalism percolated, especially in Scotland and in Flanders. Rosen navigates through the wars for Scottish independence, culminating in Robert Bruce’s great victory at Bannockburn in 1314, at just the moment that floods began and winter weather set in. Two years of rain wrecked harvests, causing famine, lawlessness, and the cattle plague and gradually plunged the continent into a century of war.

A work that glows from the author’s relish for his subject.