The Mongol Empire’s ‘Pax Mongolica’ created a period of unprecedented commercial stability. By securing trade routes with a system of ‘khans’ or rest stops, they inadvertently built a high-speed network for the plague. Logistics of death meant that fleas and rats could travel safely from the Gobi Desert to the heart of Europe, moving from one caravan to the next with ease.

In 1343, the Mongol Golden Horde besieged the port city of Caffa. When the plague decimated his own ranks, Jani Beg utilized a terrifying tactic:

• Loading infected corpses onto catapults.
• Hurling the bodies over the city walls.
• Turning an impregnable fortress into a death trap.

This event is widely considered the first recorded use of biological warfare in history.

The very items that defined status—soft silk and exotic spices—became the vessels for the plague. Fleas found the fabric bales to be an ideal, warm environment, while grain sacks provided the perfect food source for plague-carrying rats. The luxury that nobles flaunted became the literal shroud used to wrap their corpses just days later.

The tragedy of the Black Death serves as a grim reminder of how interconnected systems can facilitate disaster. Much like the psychological traps discussed in How Unfinished Conflict Hijacks Your Brain, the merchants of the 14th century were caught in a loop of greed that blinded them to the existential threat hiding in their cargo holds.