GEOGRAPHY

   The key element in the development of Mesopotamian cultures was the gradual adaptation to the ecological conditions of the region. The original homeland for Stone Age humans was the Levantine coast. The first experiments in cultivating cereals and domesticating animals occurred in this more naturally fertile region, which received a higher amount of annual rainfall. In the Neolithic period (c. 10,000–6,000 B.C.), other areas on the lee side of mountain ridges, in Syria and Anatolia, became inhabited, and the first densely occupied settlements with permanent architecture appeared. This gradual shift took place as hunting and gathering gave way as the main form of subsistence to agriculture or nomadic pastoralism. Northern Mesopotamia (between the south Anatolian mountain ridge and the latitude of present-day Baghdad) was situated in the geographical zone in which rainfall agriculture was possible. The earliest Mesopotamian settlements, dating back to the sixth millennium, were found here. Excavations at sites such as Tell Brak, Tell Arpachiya, Tepe Gawra, and Nineveh have yielded plentiful polychrome painted pottery and sometimes substantial buildings. In contrast, the alluvial plains of the south lie in one of the driest and hottest regions of the world, neighboring the great deserts of Syria and northern Arabia. The oldest archaeological sites there date from the fifth millennium and are concentrated in the marshy areas of the south. Their material remains appear simpler in comparison to the finds of the north. However, in the late fifth and throughout the fourth millennia, this began to change as the southern alluvium began to be more densely inhabited. Making use of previous experience with extensive agriculture, people began to intensify the exploitation of the fertile river valleys. This demanded much greater investment in terms of labor and expertise than in the more temperate climates but offered the potential of achieving substantial surplus yields that could feed large populations. In the following historical periods, such knowledge was perfected to allow for intensive cultivation of subsistence crops, especially barley and, later, date palm, using sophisticated systems of irrigation, crop rotation, and collective labor deployment on large parcels of land.