The Mongol conquests simply facilitated the release throughout the Middle East of centrifugal forces that had made their presence felt as early as the middle of the tenth century. In fact, many of these tendencies had never quite disappeared but had simply been obscured as peoples rallied around the common banner of Islam. The Mongol invasion of Iran was intense, bloody, and devastating. When the Mongols captured the city of Marv, for example, they reportedly killed some seven hundred thousand inhabitants, laying farmlands and entire cities to waste and carrying off thousands of Muslim artisans to Mongolia as slaves. But in larger historical terms the invasion was relatively brief. Before long, the Mongols had established an increasingly Persianized dynasty of their own in Iran, the Ilkhanids, which tried to reverse some of the devastation of the earlier decades by encouraging public works and patronizing the arts. Under their patronage, painting and manuscript illustration, the recording of history. and the building of monuments, especially tombs, flourished. The Ilkhanids collapsed by 1336, and a succession of smaller states emerged in areas previously under their control. A similar fate had befallen the earlier Saljuqs, who in the middle of the eleventh century had taken control of most of Anatolia, Armenia, and Azerbaijan, only to be broken up into smaller states soon afterward. Geographic circumstances and other administrative and bureaucratic limitations had forced both the Saljuqs and the Ilkhanids to rely on local, mostly landed elites to maintain their suzerainty. This very decentralization and diffusion of power would not only germinate their own collapse but also facilitate conditions for the rise of their eventual successors, the Ottomans in Anatolia and the Safavids in Iran (Source: Political History of Middle East).