“The plague disease, caused by Yersinia pestis, is enzootic (commonly present) in populations of ground rodents in central Asia, but it is not entirely clear where the 14th century pandemic started. The most popular theory places the first cases in the steppes of Central Asia, though some speculate that it originated around northern India, and others, like scholar Michael W. Dols, argue that the historical evidence concerning epidemics in the Mediterranean and specifically the Plague of Justinian point to a probability that the Black Death originated in Africa and spread to central Asia, where it then became entrenched among the rodent population. Nevertheless, from central Asia it was carried east and west along the Silk Road, by Mongol armies and traders making use of the opportunities of free passage within the Mongol Empire offered by the Pax Mongolica. It was reportedly first introduced to Europe at the trading city of Caffa in the Crimea in 1347. After a protracted siege, during which the Mongol army under Janibeg was suffering the disease, they catapulted the infected corpses over the city walls to infect the inhabitants. The Genoese traders fled, bringing the plague by ship into Sicily and the south of Europe, whence it spread.

Whether or not this hypothesis is accurate, it is clear that several pre-existing conditions such as war, famine, and weather contributed to the severity of the Black Death. In China, the thirteenth century Mongol conquest disrupted farming and trading, and led to widespread famine. The population dropped from approximately 120 to 60 million. The 14th century plague is estimated to have killed 30% of the population of China.

In Europe, the Medieval warm period ended sometime towards the end of the fourteenth century, bringing harsher winters and reduced harvests. In the years 1315 to 1317 a catastrophic famine, known as the Great Famine, struck much of North Western Europe. The famine came about as the result of a large population growth in the previous centuries, with the result that Europe had become overpopulated in the early fourteenth century; the number of Europeans began to exceed the reduced productive capacity of the land and farmers(“Black Death - Wikipedia, the free encyclopedia”).”

In contrast to the actual history of the plague, Robinson explorers what would have happened if the entire population of western Europe had been destroyed. book one begins with Bold attempting to find civilization. During this time in limbo, he is constantly plagued by Temure the Lame's ghost who died from the plage.

“Black Death - Wikipedia, the free encyclopedia.” 26 Feb 2008 <http://en.wikipedia.org/wiki/Black_Death>.

Robinson, Kim Stanley. The Years of Rice and Salt. New York: Bantam Books, 2002.