The four essential characteristics of a state include a permanent population, definite boundaries, the ability to negotiate with other states and a single government. States meeting these requirements, laid out by international law, qualify as sovereign and are recognized as having independent control of a particular geographical area.
Sovereign states, also known as nations or countries, typically do not depend on any other state. They sometimes exist without full recognition by other sovereign states but fall short in making treaties and exercising diplomacy with other states. The concept of independent states first arose in the European feudal system as people changed their loyalties from an individual monarch to a geographic area or political group.