In all human societies, whether primitive or advanced, there have been legal norms rejecting the use of force. Norms have emerged from custom. Written law may have resulted from the codification and development of customary rules. This happened in Sweden around 1200 A.D. when a central power succeeded in wielding control and secured the unification and development of regional norms into common rules that became binding on all. Over time majority decisions became the established mode of rules adoption. In the international community, no central power has attained control and there has been no legislature adopting rules binding on all states. At Westphalia, in 1648, after the thirty years war, and in Vienna, in 1815, after the Napoleonic wars, the great powers victors felt a responsibility to design a peaceful order. However, it was only through the joint adoption of the Covenant of the League of Nations and the Charter of the UN that the states of the world agreed on binding themselves under legal norms prohibiting the use of interstate use of force.