Peace of Westphalia

The Peace of Westphalia, concluded in 1648, was a series of treaties that ended the Thirty Years' War in the Holy Roman Empire and the Eighty Years' War between Spain and the Dutch Republic. It is often treated as the birth of the modern state system, in which independent states recognize one another's territorial authority. That reputation is partly a later construction, but the settlement did reshape the political map and the way European powers justified their relations.

The Thirty Years' War began in 1618 with a revolt in Bohemia against the Habsburg Emperor Ferdinand II. What started as a conflict over religion and imperial authority widened as Denmark, Sweden, France, Spain and many German principalities joined in. Catholic and Protestant loyalties mattered, but so did dynastic rivalry; Catholic France, for instance, fought against the Catholic Habsburgs. Armies lived off the land, and war, famine and disease devastated parts of central Europe. Estimates of population loss in some German regions are very high, though historians debate the exact figures.

Negotiations took place from the mid-1640s in two Westphalian cities, Münster and Osnabrück, with Catholic and Protestant delegations meeting in separate places. This was one of the first large diplomatic congresses in European history, involving representatives from most of the continent's powers. The resulting treaties, the Treaty of Osnabrück and the Treaty of Münster, adjusted borders and compensated the victors. Sweden gained territory on the Baltic and North Sea coasts, France secured holdings in Alsace, and the independence of the Dutch Republic was recognized by Spain. The Swiss Confederation was also acknowledged as effectively separate from the Empire.

Within the Empire, the settlement confirmed the principle of the earlier Peace of Augsburg and extended it to include Calvinists alongside Lutherans and Catholics. It also strengthened the rights of the Empire's many princes and territories, including their ability to make alliances, as long as these were not aimed at the emperor or the Empire. This left the emperor with less power over the German lands and the Empire as a loose, layered structure.

The idea that Westphalia created national sovereignty and a doctrine of non-interference is a simplification. The treaties did not use the language of modern sovereignty, and powers continued to intervene in one another's affairs, often citing the treaties themselves as justification. Many historians argue that the "Westphalian system" was a story told by later generations, especially in the nineteenth and twentieth centuries. Even so, the peace marked a turning point: religion became less central as a cause of large-scale war in Europe, and diplomacy by treaty and congress became established practice. Its name remains a shorthand for the principle of state sovereignty in international relations.