The Peace of Westphalia
The Treaty of Westphalia signed in 1648 brought an end to the Eighty Years War between Spain and the Dutch and the German phase of the Thirty Years War fought largely within the Holy Roman Empire. Three separate treaties constitute the peace settlement, the Peace of Münster, the Treaty of Münster and the Treaty of Osnabrück. England, Poland, Russia, and the Ottoman Empire were the only European powers not represented at the assemblies at which the Treaty was signed. The Peace established a framework for modem international relations, with concepts of state sovereignty, inviolable borders, non-interference in internal affairs of another state, mediation between nations, and diplomacy. The Treaty of Concordia, also signed in 1648, divided the island of Saint Martin between France and the Netherlands; the Peace of Augsburg, signed in 1555, made the legal division of Christianity permanent within the Holy Roman Empire, allowing rulers to choose either Lutheranism or Roman Catholicism as the official confession of their state; the Peace of Rueil, signed in 1649, ended the first hostilities of the Fronde, civil wars in France between 1648 and 1653.
