National states are political entities characterized by defined territorial boundaries, a permanent population, and a government that exercises sovereignty over its affairs. They often have a shared identity, culture, or language among their citizens, which helps to foster a sense of unity and belonging. Examples of national states include France, Japan, and Brazil. The concept of national states emerged in the 17th century and became more prominent with the Treaty of Westphalia in 1648, which established the principles of state sovereignty and territorial integrity. National states play a crucial role in international relations, as they interact with one another through diplomacy, trade, and treaties.