The availability of raw materials is a historical factor of great importance, as is the dependence on those materials that had to be imported. In Mesopotamia, agricultural products and those from stock breeding, fisheries, date palm cultivation, and reed industries—in short, grain, vegetables, meat, leather, wool, horn, fish, dates, and reed and plant-fibre products—were available in plenty and could EASILY be PRODUCED in excess of home requirements to be exported. There are bitumen springs at Hīt (90 miles northwest of Baghdad) on the Euphrates (the Is of Herodotus). On the other hand, wood, stone, and metal were rare or even entirely ABSENT. The date palm—virtually the national tree of Iraq—yields a wood suitable only for rough beams and not for FINER work. Stone is mostly lacking in southern Mesopotamia, although limestone is quarried in the DESERT about 35 miles to the west and “Mosul marble” is found not far from the Tigris in its middle reaches. Metal can only be obtained in the mountains, and the same is true of precious and semiprecious stones. Consequently, southern Mesopotamia in particular was destined to be a land of trade from the start. Only rarely could “empires” extending over a wider area guarantee themselves imports by plundering or by subjecting neighbouring regions.