Lamp in the form of a bird

As central control weakened in the Abbasid Empire, regional dynasties arose to support, challenge, or redefine the authority of the caliph in Baghdad. The arts flourished in many centers, and wealthy merchant and professional classes emerged. A dramatic increase in productivity and innovation and an unprecedented expansion of figural decoration characterize the arts of this period. A transforming event was the influx of Turkic and Mongol peoples from Central and Inner Asia. Most of the objects in this case were created in lands ruled by the most important of the Turkic dynasties, the Great Seljuks (1038–1157), and their immediate successors, the Atabegs. The Mongol invasions into Islamic lands began in the early 1200s and culminated in the 1258 sack of Baghdad. Eventually, the Mongols established their rule as the Yuan dynasty in China, the Chagatay Khanate in Central Asia, the Golden Horde Khanate in southern Russia, and the Ilkhanid dynasty (1256–1335) in greater Iran. The integration of a vast Eurasian territory into the Mongol Empire facilitated commerce and communication, bringing fresh Chinese inspiration into Islamic art.