Mesopotamia was a collection of varied cultures whose only real bond was that of their script, their gods and their attitude toward women. The social customs, laws and even language of Akkad, for example, cannot be assumed to correspond to those of Babylon; it does seem, however, that the rights of women, the importance of literacy and the pantheon of the gods did, indeed, do so. As a result of this, Mesopotamia should be more properly understood as a region which produced multiple empires and civilizations rather than any single civilization.
This ancient civilization began around 9000 C.E. as small farming communities. These small communities or bands, cultivated wheat and barley. They were also the first to domesticate animals. Slowly but surely, these small bands began migrating together and formed even larger communties that will eventually become some of the greatest cities in ancient history.
The history and culture of Mesopotamian civilization is inextricably connected to the ebb and flow of the Tigris and Euphrates Rivers. The earliest communities developed to the north but since rainfall in that area was so unpredictable, by 5000 B.C. communities had spread south to the rich alluvial plain.
The economy of these communities was primarily agricultural and approximately 100-200 people lived in these permanently established villages. The alluvial plain in southern Mesopotamia ("land between the rivers") was far more fertile than the north but because there was little rainfall, irrigation ditches had to be constructed.
The scene for the first civilization was the north eastern section of what we today call the Middle East, along the great rivers that led to the Persian Gulf. The agents were a newly-arrived people called the Sumerians.
Hammurabi was an Amorite king who came to the throne of Babylon around 1750 B.C. During his 50-year reign, he managed to carve out a small empire that stretched from the Persian Gulf to the borders of Anatolia. He is most famed for his law code. The law code itself includes nearly 300 paragraphs of legal provisions which set forth the law of Hammurabi. It was not the first of its kind. It borrowed heavily from the old Sumerian legal system.
Some factors contributed to the fall of Mesopotamia. Overcrowding led to pollution. War-like tribes trying for geographic influence and too much irrigation. They had irrigated all the way to the sea and the soil was ruined by salt. After the Hittites withdrew, nothing much was known about the next four centuries, a dark ages.