The Westphalian System is a doctrine in international law that has been the generally accepted norm for the world order in the past couple of centuries. The basis of this doctrine is the Peace of Westphalia that put an end to the Thirty Years’ War in Europe in 1648.
The Thirty Years’ War (1618-1648) proved to be one of the most devastating wars in Europe’s history, one that left around eight million casualties. The war initially started over post-Reformation religious disputes between the Protestant and the Catholic states in the Holy Roman Empire. However, it later grew into an ongoing continental power struggle between the Habsburg Empire and the Bourbon Empire for the fate of Europe, where the Habsburgs and their Catholic allies closed ranks against an alliance of the Protestant anti-Habsburgians and the Catholic Bourbon Empire. That bloody war was concluded by the Peace of Westphalia.