Final answer:
The Peace of Westphalia ended the Thirty Years' War in 1648 and is a seminal moment in the emergence of the European state, establishing state sovereignty and the principles that shaped modern international relations.
Step-by-step explanation:
The Peace of Westphalia marked the end of the Thirty Years' War. This significant event in 1648 signalled the start of a new era in the European state system by establishing the concept of state sovereignty and the modern international order. The Westphalian treaties recognized the full territorial sovereignty of the member states of the Holy Roman Empire, a collection of nearly one thousand separate, semi-autonomous entities. T
he principles developed from Westphalia laid the foundations for the creation of individual nation-states and influenced the structure of modern diplomacy and international relations, fostering the emergence of the European state from a complex network of feudal territories and jurisdictions.