Individual settlements became cities when humans were able to produce more food than needed. The population also increased, so more artisans were needed. With the construction of palaces for rulers and huge temples, the cities became important centres in which writers, officers, soldiers, and priests lived and had a lot of influence on people. The oldest cities whose remains have been found are Jericho in Palestine (around 9000 BC) and Catal Huyuk in Turkey (around 6000 BC).
