15 May

This was a series of peace treaties signed between May and October 1648 in the Westphalian cities of Osnabrück and Münster. These treaties ended the Thirty Years’ War (1618–1648) in the Holy Roman Empire, and the Eighty Years’ War (1568–1648) between Spain and the Dutch Republic, with Spain formally recognizing the independence of the Dutch Republic.

The peace negotiations involved a total of 109 delegations representing European powers, including Holy Roman Emperor Ferdinand III, Philip IV of Spain, the Kingdom of France, the Swedish Empire, the Dutch Republic, the Princes of the Holy Roman Empire and sovereigns of the free imperial cities. The treaties that comprised the peace settlement were:

  • The Peace of Münster between the Dutch Republic and the Kingdom of Spain on 30 January 1648, ratified in Münster on 15 May 1648; and
  • Two complementary treaties both signed on 24 October 1648, namely:
    • The Treaty of Münster between the Holy Roman Emperor and France and their respective allies.
    • The Treaty of Osnabrück involving the Holy Roman Empire, Sweden and their respective allies.

The treaties did not restore peace throughout Europe, but they did create a basis for national self-determination.

The Peace of Westphalia established the precedent of peace established by diplomatic congress, and a new system of political order in central Europe, later called Westphalian sovereignty, based upon the concept of co-existing sovereign states. Inter-state aggression was to be held in check by a balance of power. A norm was established against interference in another state’s domestic affairs. As European influence spread across the globe, these Westphalian principles, especially the concept of sovereign states, became central to international law and to the prevailing world order.