According to this theory of social contract there are three stages through which human society passed and took the shape of the state. These are the three stages: A state of nature,The social contract and The civil society or the State
According to Force theory of government also known as force theory of state, the state was born as a result of force i.e. aggression, war, conquest and subjugation. In ancient times a strong man with the help of his supporters dominated the weaker people of his tribe and established the political relation of command and obedience.
Divine right of kings theory is an old theory of sate. In those days people were not civilized and did not have much knowledge. Religion was very powerful. As the time passed this theory was further developed.
A unitary state is one which is not made up of territorial divisions, which are states by themselves. The central government is all powerful. Unitary State is also known as a simple state. A composite state is one which is itself a group of constituent states. There are two types of composite state, if it consists only one region is called non-orthogonal composite state.
In common parlance State is a country considered as an organized Political community by one government . Some times, a republic or federations forming part of a country are also called states where as they can't be termed as states in political sense. Anyhow when we used the term state in the field of international relation