主题：苍狼与白鹿4中的历史 -- 五藤高庆

The Mongols probably halved the population of China. Even when the population of cities was spared, the previous population levels could often not be maintained because the Mongols had, on the way to the cities, killed nearly all the farmers and farm workers who had fed the cities. Conquered cities often rebelled after submission because of that. Many historians find it difficult to believe that so many people could have been killed by the Mongols, because where cities were occasionally spared only the countryside dwellers had been directly killed by Mongol butchery. But the Mongols destroyed the carrying capacity of the farms because they wanted grasslands for their horses and hunting parks for wild animals, so countryside murders and city massacre was the general rule until Yelu Ch’u-ts’ai, convinced Kublai Khan that it was better to spare the population of Kaifeng, turning them into a source of riches and revenue rather than corpses, to enrich Karakorum.