<P> The history of international relations based on sovereign states is often traced back to the Peace of Westphalia of 1648 , a stepping stone in the development of the modern state system . Prior to this the European medieval organization of political authority was based on a vaguely hierarchical religious order . Contrary to popular belief , Westphalia still embodied layered systems of sovereignty , especially within the Holy Roman Empire . More than the Peace of Westphalia , the Treaty of Utrecht of 1713 is thought to reflect an emerging norm that sovereigns had no internal equals within a defined territory and no external superiors as the ultimate authority within the territory 's sovereign borders . </P>
what is an international system in international relations
norm that sovereigns had no internal equals within a defined territory and no external superiors as the ultimate authority within the territory 's sovereign borders