What city and why became the most important in the ancient Mesopotamia?

At the time of the Ancient East, back in the 3rd millennium BC. the city of Babylon arose. In the 2nd millennium BC. this city became a major center of the Babylonian state. True, in the 15th century BC. Babylon was conquered by the Kassite tribes and in fact fell into decay. The revival of this ancient city took place in the 7th century BC. Then the city became the center of the cultural, commercial and political life of the Ancient East.