The 13th century was a tumultuous time in China. The region was divided into Song and Jin dynasties, with constant warfare between them and against rebelling va

The 13th century was a tumultuous time in China. The region was divided into Song and Jin dynasties, with constant warfare between them and against rebelling vassal states even before Genghis Khan appeared on the scene. When the Mongols arrived, Song formed an alliance with them and participated in a joint campaign that led to the collapse of Jin. But the Mongols didn't stop there, so what followed was an exhausting 40-year war between Song and the Mongols for control of Southern China. Nearly every other country in the region was involved in this war at one point or another, from Vietnam to Korea to Japan. Yunnan province, where the Plague is/was often said to have originated, was its own country back then and was an important Mongol ally as well. There's no doubt that all this warfare laid a fertile ground for pestilence to spread. But a lot of people would have either died or went into hiding just because of the war. This makes it very difficult to say how many people died of the Plague versus the war.