"In 1502, the Catholic Church owned 75% of the money in France and in 1522, it owned 50% of the wealth in Germany. In the early 1500's in Scotland, the Catholic Church owned more than 50% of the real estate. The control of such massive wealth excited the envy of secular rulers and merchants alike and led to the strong support of the Reformation by many secular rulers in Germany and Switzerland" (Mackenney 1993: 51).
The most famous excess of the Roman Catholic Church during the period of the Protestant Reformation was the sale of indulgences. An indulgence in and of itself is nothing sinister, but in the Catholic Church, an indulgence is used to signify a reduction of worldly punishment due to sin, the guilt of which has already been absolved (during Confession). Common means of gaining indulgences include prayer, fasting, giving alms and going on pilgrimages. However, in the 15th and 16th centuries indulgences were also granted for money. Typically, the Church sold indulgences to either finance wars or (a bit more noble reason) to finish the Sistine Chapel. Matthew was often used as the somewhat dubious theological basis for the sale of indulgences:.
"And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven" (The Catholic Living Bible 1971: Matt. 16:19).
Of course, the idea of selling "a remission of worldly punishment due to sin" is a concept ripe for abuse. In 1476, Sixtus IV declared that indulgences could be applied to people in purgatory, so peasants began buying indulgences to get family members out of purgatory (a place which the Reformers later stated didn't exist).
In 1517, Pope Leo X took things a bit further by announcing a blue light special ("feste dies" - jubilee bargain) on indulgences. Indulgences bought during this period were not just for already committed sins, but also for sins not yet committed.