Climate: "mostly desert; mild to cool winters with dry, hot, cloudless summers; northern mountainous regions along Iranian and Turkish borders experience cold winters with occasionally heavy snows that melt in early spring, sometimes causing extensive flooding in central and southern IraqContemporary Iraq occupies the territory that historians traditionally have considered the site of the earliest civilizations of the ancient Near East. Geographically, modern Iraq corresponds to the Mesopotamia of the Old Testament and of other, older, Near Eastern texts. In Western mythology and religious tradition, the land of Mesopotamia in the ancient period was a land of lush vegetation, abundant wildlife, and copious if unpredictable water resources. As such, at a very early date it attracted people from neighboring, but less hospitable areas. By 6000 B.C., Mesopotamia had been settled, chiefly by migrants from the Turkish and Iranian highlands.
The civilized life that emerged at Sumer was shaped by two conflicting factors: the unpredictability of the Tigris and Euphrates rivers, which at any time could unleash devastating floods that wiped out entire peoples, and the extreme fecundity of the river valleys, caused by centuries-old deposits of soil. Thus, while the river valleys of southern Mesopotamia attracted migrations of neighboring peoples and made possible, for the first time in history, the growing of surplus food, the volatility of the rivers necessitated a form of collective management to protect the marshy, low-lying land from flooding. As surplus production increased and as collective management became more advanced, a process of urbanization evolved and Sumerian civilization took root.
Sumer is the ancient name for southern Mesopotamia. Historians are divided on when the Sumerians arrived in the area, but they agree that the population of Sumer was a mixture of linguistic and ethnic groups that included the earlier inhabitants of the region. Sumerian culture mixed foreign and local elements. The Sumerians were highly innovative people who responded creatively to the challenges of the changeable Tigris and Euphrates rivers. Many of the great Sumerian legacies, such as writing, irrigation, the wheel, astronomy, and literature, can be seen as adaptive responses to the great rivers.
The Sumerians were the first people known to have devised a scheme of written representation as a means of communication. From the earliest writings, which were pictograms (simplified pictures on clay tablets), the Sumerians gradually created cuneiform--a way of arranging impressions stamped on clay by the wedge-like section of a chopped-off reed. The use of combinations of the same basic wedge shape to stand for phonetic, and possibly for syllabic, elements provided more flexible communication than the pictogram. Through writing, the Sumerians were able to pass on complex agricultural techniques to successive generations; this led to marked improvements in agricultural production.
Another important Sumerian legacy was the recording of literature. The most famous Sumerian epic and the one that has survived in the most nearly complete form is the epic of Gilgamesh. The story of Gilgamesh, who actually was king of the city-state of Uruk in approximately 2700 B.C., is a moving story of the ruler's deep sorrow at the death of his friend and of his consequent search for immortality. Other central themes of the story are a devastating flood and the tenuous nature of man's existence. Laden with complex abstractions and emotional expressions, the epic of Gilgamesh reflects the intellectual sophistication of the Sumerians, and it has served as the prototype for all Near Eastern inundation stories.
The precariousness of existence in southern Mesopotamia also led to a highly developed sense of religion. Cult centers such as Eridu, dating back to 5000 B.C., served as important centers of pilgrimage and devotion even before the rise of Sumer. Many of the most important Mesopotamian cities emerged in areas surrounding the pre-Sumerian cult centers, thus reinforcing the close relationship between religion and government.
The Sumerians were pantheistic; their gods more or less personified local elements and natural forces. In exchange for sacrifice and adherence to an elaborate ritual, the gods of ancient Sumer were to provide the individual with security and prosperity. A powerful priesthood emerged to oversee ritual practices and to intervene with the gods. Sumerian religious beliefs also had important political aspects. Decisions relating to land rentals, agricultural questions, trade, commercial relations, and war were determined by the priesthood, because all property belonged to the gods. The priests ruled from their temples, called ziggurats, which were essentially artificial mountains of sunbaked brick, built with outside staircases that tapered toward a shrine at the top.