Answer:
. The Black Death and bubonic plague
Explanation:
Some historians consider that Mongols conquest of Eurasia in the 13th and 14th centuries caused to spread the "plague responsible for the bubonic plague leading to the dark episode known as "Black Death".
This was a time where conditions of war, famine and plague ceased the demographic growth in the territories the Mongols ruled.
It is widely believed that the plague went through the Silk Road and was propelled by Mongols in that the merchant's caravans coming from Asia spread it to Europe.
