What is a "state"? Who ruled the early states, and which segments of society usually supported the ruler?

A state can be defined as a 'political community' which gathers under one leader and abide by a specfic set of rules and laws.

The early states as those seen in the Sumer, where city-states. Small in size, ruled by a king with the support of the local people and land lords.

The ruler also had a small army to maintain local order and to protect against foriegn invasions.