What is causing the deaths of people in Poe's short story "The Masque of the Red Death"?
In Edgar Allan Poe's "The Masque of the Red Death," the people enclosed in Prospero's abbey have gathered there to evade the plague, which is raging outside, all around them:
It was toward the close of the fifth or sixth month of his seclusion, and while the pestilence raged most furiously abroad, that the Prince Prospero entertained his thousand friends at a masked ball of the most unusual magnificence.
Historically, several deadly outbreaks of plague ravaged Europe (often referred to as the Black Death). During this time, wealthy people (most notably kings and their families) would lock themselves within rooms in their castles to avoid contracting the highly contagious—and most often deadly—disease. (In the five years that followed the plague's introduction from the East into Europe—in the mid-1300s—20 million lives were lost.)
Readers of the time, though separated by those events by hundreds of years, could understand the terror the people in the story would have been experiencing. It would not be a surprise, either, that Prince Prospero has used his enormous wealth to protect his many guests for several months. (It is notably macabre that a thousand people would party for months to distract themselves while thousands were dying outside the abbey walls.) However, as was the case in Europe during the plague years, it was nearly impossible to remain unscathed, because the disease thrived where many people were gathered (towns, cities, etc.).
The narrator makes note of the arrival of the Red Death. At first Prospero and his guests believe it to be someone that has callously and viciously worn a costume depicting a diseased dead body. Prospero demands:
...who dares insult us with this blasphemous mockery.
Everyone is petrified to take hold of the figure that moves from room to room. His costume resembles an eroding corpse—covered also with gore and spatters of blood. Enraged, Prospero pulls his courage about him and races into the room where the figure has wandered, unimpeded. Preparing to strike out at the phantom with a dagger, Prospero succumbs to the plague. Suddenly a group of onlookers attack the loathsome figure, only to find that it is not a man at all, but empty ("untenanted") clothing. The people:
...gasped in unutterable horror at finding the grave-cerements and corpse-like mask which they handled with so violent a rudeness, untenanted by any tangible form.
It is at this moment that all those present realize who (or what) their fellow guest truly is:
And now was acknowledged the presence of the Red Death. He had come like a thief in the night.
One after another, each guest succumbs to the plague and dies.
Poe points out that the plague favored—and spared—no one, even in light of prominence or wealth. He uses the Biblical quote "come like a thief in the night" (1 Thessalonians 5:2), referring to the sudden appearance of the Red Death.
Allegorically, the author points out two things about death: that it comes stealthily to rob one of life (like a "thief"), and that death is "no respecter of persons" (Acts 10:34, KJV): no one can escape the inevitable end of life.
A plague called the Red Death is sweeping across Europe at the time of the story. It is called the Red Death because one of the symptoms is splotchy red marks on the body. Like the bubonic plague or Black Death in real history, it devastates whole populations of people. That is why Prince Prospero gathers up 1000 or so of his friends and locks them and himself away in the abbey of his castle. Everything goes well until the night of a masquerade ball. During the party, a stranger appears amidst the guests. He is dressed in tattered clothes from the grave and wears a mask that looks like a corpse. Prince Prospero tries to kill him but dies when he gets near the stranger. The stranger, is in fact, symbolic of the disease, the Red Death. Everyone at the ball soon dies. Poe's purpose in writing this story is to let the reader know that one cannot escape one's fate and that death is inevitable.