An example where the balance of power was forming was that of England when they decided on a foreign policy that would preserve the balance between Spain and the France, which later evolved towards the balance of power. policy. There have been many attempts to falsify the balance of power theory; some realists have pointed to cases in international systems other than modern Europe where balance has failed. The balance of power first came into force internationally in Europe in the 17th century, following the Treaty of Westphalia of 1648. This peace formalized a system that had emerged among the great European powers early in the 'era. of the century, including the recognition of the sovereignty of States in the international system. States, eager to find a path to secular peace after roughly a century of wars based on religious and ideological differences, gradually adopted the logic underlying balance of power theory and, by the end of the 17th century, this was the approach of European nations. States in international relations and foreign policy. During this period, Britain became accustomed to exploiting this system to its advantage, regularly acting as a balancer to check hegemonic aspirations and becoming a central power in determining the balance of the European system. It was a role that Britain would continue to play throughout the 17th and 18th centuries and