we have proved that 8000 years ago, the Sumerites, who inhabited Babylonia, were living in walled cities. One can only conjecture for how many centuries previous such cities had existed. Their inhabitants were not mere barbarians living within protecting walls. They were an educated and enlightened people. So far as written history goes, they were the first engineers, the first astronomers, the first mathematicians, the first financiers and the first people to have a written language.
Mention has already been made of the irrigation systems which transformed the arid valley into an agricultural paradise.