After the Golden Age - which is usually dated back to early Abbasid period - things began to change in the Middle East. Population decreased, ancient cities declined or were even deserted, and barbaric nomadism spread at the expense of civilized agriculture. In a parallel process intellectual creativity was stifled and artistic originality dried up. Thus even before the capitalist world economy made its influence felt, the once dynamic civilizations of the Middle East were turning into stagnate proto-developing countries: impoverished, disease-ridden and technologically backward.
The present study asks a few simple questions about this notion of decline: How extensive and how general was the contraction of agriculture and de-urbanization? What kinds of explanations can we offer?
Taking the long view of Iranshahr's history, the author is enabled to discern certain broad patterns in the continuous changes and fluctuations. Although the patterns are not altogether consistent with the notion of decline in the Middle East, what stands out as a overall picture is the considerable expansion of settlement and irrigation occuring in Parthian and Sassanian times - largely a result of a royal policy of colonization - and the progressing environmental collapse in Mesopotamia in the following centuries, draining away the strength of the Persian Empires.
Nature, whether pristine or coerced and modified by human agency, will in all socities set specific limiting conditions. In Iranshahr the limits were narrower than in most other places. From this it does not follow, however, that the decline was an unavoidable result of the severe environmental conditions. Though the fate of Iranshahr certainly emphasizes that society and nature constitute a single system, this does not lead into the trap of ecological reductionism.