The problem with living in a hunter/gatherer society is that all members of a group are engaged in either raising and protecting the young or in gathering food to feed the group. As a result of this early man lived in communities that were very small in number and often mobile. Those that were not as mobile managed to stay in the one area by supplementing their diet with wild barley, wheat and other plant based foods that were naturally available in certain areas.
It is estimated that somewhere around 8000 BC some of these small groups began to discover the secrets of planting and reaping the wild wheat and barley that grew in the Near East, while those living on the plains learnt to domesticate sheep, goats and geese. This was a significant event in that it allowed the groups to become more stable, not needing to move about as much in search of food. It also had the effect of creating a boom in human population, and what had once been small bands of people slowly became small communities.
On the plains and in the semi-arid deserts of Syria, nomadic people moved their herds from place to place in search of good pastures while their wheat and barley growing cousins lived in the hills where the natural rainfall was sufficient for their crops to grow (around 300mm). In some areas these communities set up semi-permanent dwellings, some becoming small villages and 'proto-cities' such as Jericho in the Jordan valley and Catal Huyuk in the Taurus mountains in eastern Anatolia (modern Turkey).
Despite these small communities forming, it was not until the development of irrigation, a process that developed between 6000 BC and 4000 BC, that communities really started to grow. With irrigation the mountain dwelling people could move to the river plains where there was a constant source of water and grow regular crops, no longer relying on the rain that could neither be controlled nor predicted.
Eventually these riverside settlements grew in size from villages to small towns and a culture started to develop which has become known as the Ubaid culture. The advantage that these towns has was that they no longer required every person to be dedicated to gathering food. The crops could be managed by fewer people, allowing others to devote themselves to other disciplines such as building, mathematics and religion.
Trade developed between these towns and such far away places as Egypt and the Indus Valley communities of modern Pakistan and India, as well as between the towns and the nomadic pastoralists who lived along the Arabian Peninsular. Many of these people gave up the nomadic life and settled in the towns, swelling their size even further. By 3500 BC a group of people we call today the Sumerians, who we have been unable to trace their origins, were firmly in control of all the cities in the region between the lower Euphrates and Tigris rivers. Urban society had begun.
