Published online by Cambridge University Press: 27 May 2014
Mesopotamia is an elongated basin running from Syria south-eastwards to the Persian Gulf. It is bordered on the south-west by the Arabian massif, on the north by the mountains of Anatolia, and on the east by the Zagros range. Agriculture in this basin is controlled by climate to an extent unknown in Europe, particularly by water supply, which may come from rainfall or from rivers that flow out of the mountains. The modern boundary of rainfall sufficient for agriculture, which for practical purposes may be taken as 200 mm or 8 in reliable annual aggregate, runs across northern Mesopotamia from west to east and then turns south-east, following the foothills of the Zagros (fig. 1). We have at present no reason to think that this approximate boundary has shifted appreciably during the period with which we are concerned, although there were almost certainly marginal fluctuations. The limited palynological evidence, which comes from the mountainous regions north and east of Mesopotamia, suggests that after about 12000 bc both temperature and precipitation gradually increased and that by about 9000 bc oak and pistachio trees were beginning to reinvade the Zagros foothills, an area from which they had been eradicated during the cooler temperatures of the last glacial period (van Zeist and Wright 1963; Wright 1968; van Zeist 1969).