1. Trade Routes: The Silk Road, a network of trade routes connecting Asia, Europe, and Africa, played a significant role in the spread of the plague. Infected rodents, likely carried by merchant ships or caravans, traveled along these routes, bringing the disease to port cities and inland areas.
2. Mongolian Invasions: In the mid-13th century, the Mongol Empire, under the leadership of Genghis Khan, expanded rapidly across Asia and into parts of Europe. During their military campaigns, the Mongols often used siege warfare, during which they would catapult infected animal carcasses over city walls to spread disease among the besieged population.
3. Italian Merchant Ships: In the 14th century, Italian merchant ships trading with the Black Sea region inadvertently transported infected rats and fleas to Europe. The port cities of Genoa and Venice, which had extensive trade connections, became early epicenters of the outbreak in Europe.
4. Spread Within Europe: Once the plague was introduced to Europe, it spread rapidly due to several factors. Poor sanitation, crowded living conditions, and limited medical knowledge contributed to the disease's transmission. The plague was carried by fleas that lived on rats and other rodents, which were abundant in medieval European cities.
The Black Plague had a devastating impact on Europe, killing an estimated 75-200 million people, roughly 30-50% of the European population at the time. It triggered social, economic, religious, and cultural changes that shaped the course of European history.