Congress of Westphalia (1644–48). The congress at which an end to the Thirty Years’ War was negotiated.The main fruits of the negotiations were the two treaties of peace signed on 24 October 1648 known collectively as either the “Treaty” or the “Peace” of Westphalia. They are generally reckoned to have resolved the structure and codified the constitutional rules of the European statessystem as it had emerged from the unity of medieval Christendom. Thereafter, it has not been unusual to see the term “Westphalian system” used to describe the post-1648 system of international relations, i.e. that in which states – secular, sovereign, independent, and equal – are the members, and stability is preserved by the balance of power, diplomacy and international law. Thereofre, the correct option is B.