The Mongol Empire declined mostly due to the deadly Bubonic Plague. “It began in the 1330s in China, where it killed as much as half the population in just twenty years,” (The Mongol World). This disease made the empire crumble reducing trade and then moving along some major trade networks. The Bubonic plague also spread to Southern Asia and Europe when people traveled with the plague on them that allowed the bacteria to spread to new places, (Placard P). Other diseases such as smallpox, and measles were other epidemics that helped wipe out populations causing their empires to