In the ancient world, Mesopotamia was a treasured tract of land between the Tigris and Euphrates Rivers in present day Iraq. It was highly valued because of its potential for agricultural surpluses that the fertile river valley promised. Mesopotamia was an easy target because the area offers few natural boundaries for protection. Civilization developed out of Mesopotamia in the form of city-states that flourished on the southern end of the rivers.
Because of the attraction of the river valley and the lack of boundaries for protection, Mesopotamia was a hot spot for militarism and warfare. The first ruler to exert authority over all of the city states was Sargon of Akkadia. His empire was eventually conquered by the Babylonians under Hammurabi. The Elamites, Asssyrians, Chaldeans and Persians all took turns ruling over Mesopotamia. They were followed by the Seleucids of Alexander the Great’s empire and in later times the Romans.
Mesopotamia is a vast area with many important cities and a long, rich history. It is difficult to quantify the number of conquests without having more specifics with regards to the area being referenced and the time frame.