Shen-tsung, the 6th Emperor of Sung dynasty, received two ambassadors successively from so-called the Western Regions, one sent by the Sultanate of Seljukides, and the other by the East Roman Empire. These two countries confronted keenly each other and the antagonism was the cause of Crusade. The war devastated the Middle East, resulting in a great loss of population. The Seljukides had to recruit