This terrible pestilence, which is perhaps the worst visitation in all recorded history, has lent itself in our day to a great deal of exaggeration and special pleading; it is frequently invoked as a deus ex machina to explain inconvenient facts away. But, when all exaggerations have been discounted, it still remains one of the most important events of our whole period. In this chapter, I shall deal mainly with its effects upon men's worldoutlook in England.

Doctors are now agreed that this was the bubonic plague, coming from the East, and carried by fleas and rats, of which there was no lack in medieval Europe. Medieval medicine was naturally powerless to diagnose anything so dependent upon steady and microscopic observation; the plague was therefore often attributed secondarily to planetary influences, and primarily to God's anger against the special wickedness of the age.