Mesopotamia was named the area between Tigris and Euphrates rivers, there appeared and developed he first major cultures of Sumerians, Akkadians, Babylonians, Assyrians and others. In the southern part of Mesopotamia, where Euphrates meet the sea, up to -7000 was an empty from humans place full of mud. From -6000 the view of the passers-by changed, they understood the usefulness of the mud and the fertility of the soil, people began to settle down; the first inhabitants were named Sumerians.
They first made straw huts but soon they bake the mud and made bricks, with the bricks built houses and villages. With proper water management and the evolution of agriculture a rapid increase in population took place, villages became cities. Around -5000 there were many powerful autonomous city-states with a population of 40 or 50 thousands. From the family agricultural economy, the first organized society had been created. The cities had to coordinate with each other for the management of the waters, so they gradually joined a coalition in which the leadership were exercised - with alternations - by the cities of Eridu, Kish, Ur, Uruk.
Each city had a patron god and a ruler who was considered to be the representative of this god on earth; the ruler was at the same time high priest, judge and leader of the army. Occasionally they campaigned against each other, and each time, the victorious ruler shared the conquered land and the newly-acquired slaves with his leaders. He ruled with the help of these leaders, members of his family and the priesthood. Society was in the form of a pyramid. The upper courtiers and priests were on top, while at the base were the farmers and merchants . The slaves were mainly prisoners of war but gradually and free citizens began to lose their freedom due to debt. The well-fortified cities with great walls adorned large palaces with original temples of zigurats. The zigurat looked like a stepped pyramid with a small temple at its top. Apart from a place of worship, it was also the center of many other activities, such as Command, Treasury, and Warehouse.
Administration revenue came from taxes. Public works were made by slaves. Gradually the cities filled with temples, and the gods multiplied like the priests. The people were obliged to supply the temples with food and girls for God, which were enjoyed by the representatives of the gods, namely the priests. The service of the young girls in the temples was a reason of pride for their family. The greed of the priests continually grew, just like their wealth and power. There was a time when countless tax collectors roamed the streets and almost enforced taxes for temples in every opportunity such as birth, marriage, buying, selling, death, celebration. We learn from the Sumerian sacred books that the most beloved king was Uragagina, who managed to limit the priests and lighten people from the overwhelming taxes.
The Sumerians developed empirical knowledge of geometry, arithmetic and medicine, dealt with astrology and then with astronomy. Works of art have been saved, pictures of everyday life as well as miniature craftsmanship. Music seems to have played an important role in their lives as musical instruments have been preserved, while authentic harps were found in royal tombs.
Around -2600 some climatic factors led to an unprecedented catastrophe for any historical period. A long period of heavy rainfall had led the great rivers of Mesopotamia to flood to a vast extent, destroying all of the excellent irrigation network and destroying entire cities. This fact passed to various religions as a divine work.
After the cataclysm, the Sumerians were weakened and around -2300 the Akkad ruler managed to conquer the Sumerian cities and put an end to the Sumerian sovereignty. The Sumerian identity began to be unified with that of the Akkads, as their gods and their language; eventually their culture was extinct and forgotten.