Pope Francis, "The worship of the ancient golden calf has returned in a new and ruthless guise...

[JDPriestly]

44. The Catholic Church is the protector of one of a good part of our immense cultural heritage.

That is a responsibility owed to mankind, not an indication of greed.

Construction of the present basilica, replacing the Old St. Peter's Basilica of the 4th century, began on 18 April 1506 and was completed on 18 November 1626.[4]

http://en.wikipedia.org/wiki/St._Peter%27s_Basilica

Shortly after the construction of St. Peter's began, Martin Luther posted his 95 Theses and the Protestant movement caught fire.

http://en.wikipedia.org/wiki/The_Ninety-Five_Theses

One of the complaints of the protestants was the sale of indulgences. That is one of the ways that the Catholic Church amassed the fortunes necessary to construct its palatial cathedrals.

The Protestant Reformation was the schism within Western Christianity initiated by Martin Luther, John Calvin, and other early Protestants. Although there had been significant attempts at reform before Luther (notably those of John Wycliffe and Jan Huss), the date most usually given for the start of the Protestant Reformation is 1517, when Luther published The Ninety-Five Theses, and for its conclusion in 1648 with the Peace of Westphalia that ended the European wars of religion.[1] Luther started by criticising the relatively recent practice of selling indulgences, but the debate widened until it touched on many of the doctrines and devotional practices of the Catholic Church.

http://en.wikipedia.org/wiki/Protestant_Reformation

What was an indulgence?

In Catholic theology, an indulgence technically is a remission of the temporal[1] punishment inflicted by the Church for a previously forgiven sin.[2][3][4] An indulgence thus does not forgive the guilt of sin nor releases from the eternal punishment which Church doctrine associates to unforgiven mortal sins. It is not a permit to commit sin, a pardon of future sin, nor a guarantee of salvation for oneself or for another.[2][5] Ordinarily, forgiveness of mortal sins is obtained through Confession (i.e., penance or reconciliation).

. . . .

Indulgences became increasingly popular in the Middle Ages as a reward for displaying piety and doing good deeds, though, doctrinally speaking, the Church stated that the indulgence was only valid for temporal punishment for sins already forgiven in the Sacrament of Confession. The faithful asked that indulgences be given for saying their favourite prayers, doing acts of devotion, attending places of worship, and going on pilgrimage; confraternities wanted indulgences for putting on performances and processions; associations demanded that their meetings be rewarded with indulgences. Good deeds included charitable donations of money for a good cause, and money thus raised was used for many righteous causes, both religious and civil; building projects funded by indulgences include churches, hospitals, leper colonies, schools, roads, and bridges.[44]

However, the later Middle Ages saw the growth of considerable abuses. Greedy commissaries sought to extract the maximum amount of money for each indulgence.[46] Professional "pardoners"[6] (quaestores in Latin) - who were sent to collect alms for a specific project - practiced the unrestricted sale of indulgences. Many of these quaestores exceeded official Church doctrine, whether in avarice or ignorant zeal, and promised rewards like salvation from eternal damnation in return for money.[44] With the permission of the Church, indulgences also became a way for Catholic rulers to fund expensive projects, such as Crusades and cathedrals, by keeping a significant portion of the money raised from indulgences in their lands.[44] There was a tendency to forge documents declaring that indulgences had been granted.[44] Indulgences grew to extraordinary magnitude, in terms of longevity and breadth of forgiveness.

http://en.wikipedia.org/wiki/Indulgence

And so sin and the money spent for absolution from sin helped build the magnificent cathedrals.