Thirty Years' War Begins — Defenestration of Prague
The Thirty Years' War (1618–1648) was the most destructive conflict in European history before the twentieth century, killing between 25–40% of the German-speaking population through battle, famine, and plague. It began on 23 May 1618 when Protestant Bohemian nobles threw two Imperial Catholic governors from the windows of Prague Castle (the 'Defenestration of Prague'), a dramatic gesture of defiance against Habsburg attempts to reimpose Catholicism in Bohemia. The war passed through four phases: the Bohemian phase (1618–1625), in which the Protestant Bohemians were crushed at the Battle of White Mountain (1620) and replaced by Catholic Habsburg administrators; the Danish phase (1625–1629), in which Denmark intervened on the Protestant side and was defeated; the Swedish phase (1630–1635), in which Sweden under Gustavus Adolphus reversed Protestant fortunes before his death at Lützen (1632); and the French phase (1635–1648), in which Catholic France under Richelieu and Mazarin intervened against the Habsburgs for geopolitical rather than religious reasons, transforming the conflict into a dynastic power struggle. The war's causes were structural: the Peace of Augsburg (1555) had settled the conflict between Lutheranism and Catholicism but excluded Calvinism, leaving a generation of religious tensions unresolved. The war ended with the Peace of Westphalia (1648), which recognised the religious and territorial status quo, granted sovereignty to German princes, and established principles of state sovereignty that shaped international relations for centuries.
- Year: 1618 CE
- Category: Military
