"Some commentators find it difficult to classify the Mongol killing as genocide, despite its widespread and frequent occurrence. Yet the Mongols often meticulously planned their campaigns against their enemies with the clear goal of eliminating all or part of the targeted population. The Mongols wiped out en masse those groups that resisted them, even to the point of returning to destroyed cities and towns that they had targeted to finish off the survivors. True, no single group or ethnicity was identified by the Mongols for elimination. In fact, no group was exempt, though craftsmen, artisans, merchants, and builders often found a home with the Mongols. Peoples like the Hungarians, the Khwarezmians, and the Chinese were attacked with a genocidal fury that seriously reduced large population groups to fractions of their previous numbers. The attempt was to destroy the groups “as such.” Unlike the Crusaders, the Mongols were not motivated by an ideology that justified destruction. Instead, killing was a method of empire building, a way to expand their territory, terrorize their opponents, and incorporate a wide variety of peoples and cultures into a vast territory stretching at some points from the Mediterranean to the Pacific. Mass killing, in some cases genocide, needed no justification. It was a fact of Mongol power and rule."