When the Plague initially swept over Europe in the Fourteenth Century it shocked the very foundations of the core institutions of European life. The Church was no exception; in fact the Church was one of the most affected institutions. The Plague polarized European reaction to Christianity: while in some cases religiosity reached a new fervor that had been unprecedented, in other cases the Church was seen as inherently corrupt, vile, and - in some cases - the actual cause of the Plague. In any case, this Plague fundamentally changed religion in Europe in the years that would follow the initial outbreak.
The reaction by the Church to the Black Plague was mixed. However, the general consensus among clerics was that the Plague was a punishment from God for the sins of the people who lived too luxurious of a lifestyle. A general belief was that God was eradicating the evil people from the Earth; as one parable states:
"Thus also God behaves in Nature when he wishes to punish sinful men; he makes a pungent smell - that is, the poisoned air. . . How quickly God can prepare such a whirlwind and make his angels blow it forth into all countries, can be read in the Apocalypse in all parts." [01]
Proposed Changes
Some of the proposed reasons for the Plague seem downright trivial by today's standards. For instance, the Spanish clergy attributed the pestilence to opera and later, English bishops blamed the theater for the Plague. Even fashion was blamed for the disease; when a new type of shoe was introduced around the time of the initial outbreak, some people believed that the shoe was an annoyance to God. Later on, in the Sixteenth Century, as to be expected, Protestants and Catholics both blamed each other for drawing God's wrath.
For the most part, the Church tried to denounce superstitious causes of the Plague: for instance, it on several occasions rejected the notion that the Plague was caused by certain conjugations of celestial bodies.
Superstition
However, this does not mean superstition was completely absent from the Church: in fact, there were a number of clerics, even popes, who publicly consulted the stars. Another developing trend that developed throughout the years of Plague was the belief that comets were responsible for the Plague. Therefore in 1532, the Pope actually excommunicated a comet. The Church took other such extraordinary and downright odd actions. For instance, a ban was placed on grubs, caterpillars, mice, rats, and locusts in the late Fifteenth Century as it was believed they might have something to do with the Plague [03]. Ironically enough, this wasn't far from the truth. Therefore even though it was the official position of the Church that superstitions were untruthful and even heretical, the beliefs in them proliferated throughout the Plague years.
Canonizations
The Church dealt
with the Plague in a number of ways. The most notable of these was that there
were an increased number of processions and vows in hopes of gaining acceptance
from God. An enormous amount of churches and pillars were erected in honor
of the Holy Trinity, the Virgin Mary, and saints such as St. Peter and St.
Sebastian. Also included was a newly canonized Saint, St. Rochus, whose story
is typical of religious heroes throughout this period. Rochus was a man who
had cared much for humanity and showed disregard for the Plague when caring
for its victims. Theological history is traced with elements of these types
of stories. Others include the Capucins and Jesuits, both of whom for the
most part selflessly helped plague victims during a large outbreak at Marseilles.
Many clerics gave the sacrament of Extreme Unction to those dying of the plague,
even though it endangered their lives. [04]
However, this is
not always how events transpired. Sometimes in fear, clerics did not faithfully
execute the sacraments. This was especially true in Italy, in which priests
were, for the most part, seized with fear of death. The most extreme case,
as written by Pompejo Pellini, was that of the city of Perugia, in which he
states that no friar or priest was available to hear confession or even converse
with the sick, and there was no one to accompany them to the grave [05].
This generally was not the case in France and Germany. 
In
some cases, Extreme Unction was given to sufferers of the Plague, but the
oil used to anoint their faces was delivered via a long stick so as to keep
the priests from becoming infected. The Plague brought out a great deal of
criticism against the Church for this. Another criticism dealt to the Church
was that it was far too greedy, especially during this time of the crisis.
As mentioned below, one immediate response to the Plague was the donation
of great amounts of property to the Church from the laity. Thus, such notions
were common as was noted by a man who wrote,
"God does not desire the death of the sinner but that he should live and pay." [07]
This perception
was only enhanced by the fact that many indulgences were offered by Popes
of the Fourteenth Century, and promises of complete absolution for pilgrimages
to Rome.
The chaos and despair of the Plague also helped bring about a renewal of religiosity
and increased piety not only among the clerics but also among the laity. As
the Plague spread throughout Europe in the middle of the Fourteenth Century
a revival of spirituality caused many people to disown their earthly possessions
and materialism. As noted by Koenigshoven,
"When in 1347 the plague was raging at Luebeck the confession was so great that the citizens, as if deprived of their senses, took leave of life and willingly renounced all earthly possessions. They bore their treasures to the monasteries and churches to lay them on the steps of the altars. But for the monks the money had no attraction, for it brought death. They closed their gates, but the people threw their money over the walls of the monasteries; they would brook no impediment in their last pious work, to which they were urged by mute despair." [08]
Another phenomenon brought about in the laity by the devastation brought on by the Plague was that of the flagellants. The flagellants were a group of people who moved from town to town and beat themselves with scourges, all the while showing complete penitence and contrition for their sins. It was believed that this self-inflicted torture symbolized the suffering of Christ and perhaps God would show mercy on the people of the continent for their sins. The French cleric Jean de Venette describes the flagellants in his 1349 journal:
"Stripped to the waist, they gathered in large groups and bands and marched in procession through the crossroads and squares of cities and good towns. There they formed circles and beat upon their backs with weighted scourges, rejoicing as they did so in loud voices and singing hymns suitable to their rite and newly composed for it." [09]
Pope Clement VI, upon hearing of these actions, banned the flagellants under threat of anathema. Unfortunately, though, the movement of the flagellants from town to town had only contributed to the spread of the plague. [11]
Flagellants