How to Understand the Thirty Years' War

Unlike some leisurely, low-intensity wars in medieval-to-modern Europe—such as the Hundred Years’ War or the War of the Spanish Succession—the Thirty Years’ War in the early 17th century was a violent, unremitting struggle that, by the time it was over, had killed about a quarter of Germany’s population.

Instructions

Difficulty: Easy

1. Germany had been shaken by the rise of Protestantism. In the early 16th century, the Protestant Reformation—led by Martin Luther—had caused an unending series of conflicts between Lutherans and Catholics. The Peace of Augsburg, signed in 1555, allowed the more than 200 German princelings to adopt the religion of their choice (and, of course, to impose their choice on the citizens in their territories).
2. Other countries were poised to take advantage of this religious strife. Because it was in such a fractious condition, Germany (or rather, the huge collection of principalities that constituted Germany) was especially vulnerable to its neighbors: France, Sweden and Denmark, and even Spain.
3. The war broke out in the German territory of Bohemia. As the King of Bohemia (and Holy Roman Emperor) lay on the brink of death in 1618, his Protestant subjects feared that he would be succeeded by a strict Catholic ruler. The Protestants—both Lutherans and Calvinists—revolted, a rebellion that soon spread to other areas of Germany. The new Holy Roman Emperor, Ferdinand II, prevailed for help to the Spanish, who were only too happy to march to his aid.
4. Denmark and Sweden were next to intervene. Both these Scandinavian countries had Lutheran rulers who were anxious to defend the position of Lutherans in their neighbors to the south. Predictably, this interference stiffened the backs of German Catholics, who prevailed on Emperor Ferdinand to take back Lutheran holdings that had been seized from the Catholic church.
5. France was next—on the side of the Protestants. One of the ironies of the Thirty Years’ War is that the staunchly Catholic country of France entered the war in 1636 on the side of the Protestants—mainly because the wily Cardinal Richelieu believed that the Catholic Habsburgs needed to be taken down a peg. As before, most of the fighting took place on German soil.
6. The Peace of Westphalia ended the war in 1648. The complexity of the Thirty Years’ War can be judged by the plenipotentiaries who attended peace negotiations, including representatives from France, Spain, Switzerland, the Netherlands, Sweden, Portugal and Vatican City. By the time it was over, the endless marching of mercenary armies back and forth over German territory had resulted in the deaths of millions of German citizens.