The Thirty Years' War (1618–1648)

The Thirty Years' War (1618-1648) transformed Europe's political and religious landscape, beginning as a Protestant-Catholic conflict in Bohemia before engulfing most European powers. This devastating series of battles reduced Germany's population by 20-30% through warfare, famine and disease. The 1648 Peace of Westphalia established modern state sovereignty, ending papal supremacy in political matters while recognizing Calvinism alongside Catholicism and Lutheranism. The war shifted military tactics toward professional standing armies and redefined international relations by creating the concept of a balance of power. Its legacy includes the decline of Habsburg dominance and the rise of France as Europe's leading power.