The article studies perceptions of the Peace of Westphalia that were formed in the fields of international relations history and the general theory of international law as a result of conflicting doctrines, with some claiming the Westphalian treaties of 1648 are of universal significance for these scientific fields, and others, conversely, denying that these treaties had any sort of influence on the formation of a modern system of international relations and the formation of international law as a legal system. The article concludes that the treaties of the Peace of Westphalia does not actually contain many of the provisions attributed to them. These norms often arise only from their interpretation. However, the critics of the treaties’ significance for the history of international relations and their international legal regulationwho focused their attention only on the verbatim text of these documents while ignoring the historical conditions surrounding their development and adoption, failed to properly assess their impact. The Westphalian Congress was the first congress in world history that was pan-European in character. Its widely representative nature, the lengthy period of time during which it was held, the content of the treaties and the universally binding nature of their provisions, as well as the protocol rules, allow us to claim that the states of this world region started to identify themselves as part of a single pan-European international community. Moreover, the Congress also saw the creation, in a relatively short time, not only of treaties, but also of customary norms of general international law that were of fundamental importance for the formation of a new system of international relations. Despite the fact that most of the provisions of the Peace Treaty of Westphalia of 1648 havean applied nature, it is by no means an insignificant medieval treaty, the only virtue of which lies in it ending the Thirty Years' War. The Peace of Westphalia is an example of the first pan-European international treaty in world historywhich formulated a number of binding norms for all states of this part of the world. To sum up, the Westphalian Peace Treaty was, a historic breakthrough the creation of treaty norms of general international law, and therefore the it should be deemed a historical milestone in the creation of international law as a legal system.