Sovereign state
In international law, a sovereign state is a nonphysical juridical entity that is represented by one centralized government that has sovereignty over a geographic area. International law defines sovereign states as having a permanent population, defined territory, one government, and the capacity to enter into relations with other sovereign states. It is also normally understood that a sovereign state is neither dependent on nor subjected to any other power or state.
The existence or disappearance of a state is a question of fact. While according to the declarative theory of statehood, a sovereign state can exist without being recognised by other sovereign states, unrecognised states will often find it hard to exercise full treaty-making powers and engage in diplomatic relations with other sovereign states.
Emergence of states
States came into existence as people "gradually transferred their allegiance from an individual sovereign (king, duke, prince) to an intangible but territorial political entity, of the state". States are but one of several political orders that emerged from feudal Europe (others being city states, leagues, and empires with universalist claims to authority.