The General Crisis of the 17th Century

The 1600s brought a burst of unusual cold — part of the Little Ice Age — and with it failed harvests, famine, and revolt across the world at almost the same time. In Europe it coincided with the Thirty Years' War (1618–1648), which began as a Protestant–Catholic conflict inside the Holy Roman Empire, drew in Spain, Denmark, Sweden, and France, and killed perhaps a third of Germany's population before the Peace of Westphalia ended it by establishing that states would not intervene in each other's religion — the origin of the modern idea of sovereignty. In the same decades China's Ming dynasty fell, Britain executed its king, and revolts broke out from Portugal to the Ottoman Empire. Historians increasingly read these scattered upheavals as one connected crisis, with a chilling planet amplifying every existing fault line at once.