Over two and a half centuries had passed since Jenghiz Khan, out of the vastness of East Asia, had irrupted into the lands of the Sir Darya and Amu Darya and smashed the Moslem Empire then stretching from the Pamir to beyond the Caspian Sea. Forty years later the Mongols, under Jenghiz Khan’s grandson Hulagu, had subjugated all the realms to the west of the Oxus, nearly as far as the Mediterranean, and were only stopped by the Egyptian Mamelukes from conquering the whole of Syria. Then, in the space of a few generations, the Empire of the Il-Khans, which Hulagu had founded, changed its character, as had happened so often in the history of western Asia, where the settled world of Persian civilization had absorbed wave after wave of invaders from the steppes. Hulagu’s descendants, and more and more of the Mongolian nobles, went over to Islam; the nomad rulers surrounded themselves with scholars and poets, building palaces and towns to their glory, and spending their time in festivities or wars against one another. Real power was wielded by the viceroys and amirs in the various provinces. As soon as one of them felt strong enough, he discovered some descendant of Jenghiz Khan, proclaimed him Khan, and in his name started wars against his neighbours in the hope of annexing their provinces.