A divided Islamic world offered feeble resistance to the Crusaders who consolidated their hold on the eastern Mediterranean and imposed their fiefdoms on the region. The Seljuks, preoccupied with defending their eastern flank against the Afghan Ghaznavids, had thinned out their western defenses. The pagan Turkish tribes across the Amu Darya on the northeastern frontiers were a constant menace....

Genghiz Khan died in 1227. Upon his death, his vast empire was divided up into five parts: (1) Mongolistan consisting of the Mongol home turf, (2) Chagtai, consisting of Khorasan and Farghana Valley, (3) Persia, ruled by the Il-Khans, (4) Russia and Kazakhstan, ruled by the Golden Hordes and (5) China. The Mongols continued their advance after Genghiz. In 1229, they planned three great...