Once the plague landed in Europe, the devastation was immediate. Civic leaders in southern Europe had no idea that this destroyer of towns had been imported; worse than that, they had no idea how to stop the disease. Mayors and monarchs turned to men of science, men of medicine, and church leaders to provide an explanation. These learned men had never seen anything like the Black Death before. They could only speculate as to its cause, and their speculations seemed to many quite useless. The only explanation that satisfied both learned and ignorant men was that the disease was a divine punishment. For the sins of the world, God was striking down humanity without mercy. The seeming randomness of its victims was a manifestation of God's unknowable will.

In the Middle Ages, the University of Paris was considered to...