Economic Power

As in all pre-modern polities, the underlying strength of the empire lay in its agri­cultural resources. By the 730s, the Caliphate incorporated about 11 million square kilometers of land.

The two key regions were Egypt and Iraq. Each defied latitude through its water resources. The Nile Valley had been one of the most important sources of wheat and barley in the later Roman Empire, alongside other foods, and wine.^[1013] Iran's Nile had been the confluence of the Tigris and the Euphrates in southern Iraq—known to the Arabs as the Sawad (“Black Earth”). Like Egypt, the primary product of the Sawad was grain.^[1014] Between them, Egypt and southern Iraq probably accounted for more than two-fifths of the total revenue of the early Abbasid caliphate, with fourth-fifths of that share coming from Iraq. No other regions of the Caliphate were as productive as Iraq or Egypt, although Ifriqiya, in North Africa, the highlands and plains of Syria, and, in Iran, the highlands of Fars and the Jibal and the plains of Khurasan all also supported high yields.^[1015]

Ideas about nomadic destruction have been discredited by archaeology, which shows no discernible change in agriculture or in settlement in the immediate wake of the conquests.^[1016] Further, while there was major disruption of the upper echelons of the defeated aristocratic elite,^[1017] the middle-ranking aristocracy and the peas­antry survived largely unscathed and, with them, the agrarian infrastructure.^[1018] The new ruling elite at first comprised the Arabian commanders and their armies; then, after 692, the Umayyads and their allies; and then, after 750, the Abbasids and their Khurasanian supporters (each civil war reducing the former imperial elite to a pro­vincial one).^[1019] Enormous private wealth was available to the new rulers: the caliphal dynasties and their governors amassed landed estates and invested their wealth in the infrastructure of irrigation.^[1020]

The conquests themselves encouraged agricultural expansion, since—in line with long-established custom—the terms of many peace treaties forbade the conquering Muslims from settling lands already under cultivation, and the evolving system of land law tended to encourage the exploitation of abandoned or uncultivated land.^[1021] At the same time, new techniques and crops were disseminated by migration and settlement. This combination of fiscal policy and settlement patterns supported ur­banization, which further stimulated the exploitation of land: for example, the impe­rial period saw the foundation of five major new urban centers in Iraq (Kufa, Basra, Wasit, Baghdad, and Samarra); Baghdad's urban population in the ninth century may have been 500,000, and Basra was probably not much smaller, making these cities the largest outside China.^[1022] Likewise, many of Khurasan's urban populations grew from the low thousands to agglomerations of over 100,000 in the ninth and tenth centuries.

The conquests also perpetuated the monetized economies of the late antique empires, uniting the gold-based North African and Mediterranean world with the silver-based Iranian plateau. Furthermore, the defeat of the former imperial elites had transferred huge reserves of bullion into the hands of the conquering armies, via loot and tribute, and through a taxation system based, even more than its Roman and Iranian precursors, upon payment in coins. This cash-based economy facilitated a sophisticated market in land and in goods, where merchants and entrepreneurs could flourish, supported by the common legal framework that emerged from the gradual elaboration of Islamic law during the eighth and ninth centuries.^[1024]

The accumulation of wealth fueled long-distance trade, which built upon the es­tablished routes of late antiquity: the Mediterranean was connected to post-Roman Germanic Europe to the north and to sub-Saharan West Africa in the south; the Iranian plateau linked to the Russian river system to the north, to China and Central Asia to the east, and to East Africa and India via the Gulf to the south. Each route carried flows of high-value commodities: salt and gold from sub- Saharan Africa; furs from Russia and Scandinavia; copper and felt from Turkic Central Asia; worked silk and ceramics from China; iron and spices from Africa and India. There was also an extensive human traffic: Africans, Slavs, and Turks were imported from the frontiers, as domestic slaves and, at an elite level, as soldiers and bureaucrats; although the Sawad is the only region where the intensive use of agricultural slavery is attested.^[1025]