Two priests are visiting Rome. As they look up in awe at the splendor of St. Peter's basilica, one asks, "How much do you think it cost?"
His companion answers, "Oh, about half of Europe."The joke, of course, is that the Reformation was prompted in part by John Tetzel's sale of indulgences, and that the money from the indulgences was meant to pay for the construction of St. Peter's. German princes, unhappy about sending their treasure across the Alps to support the lavish spending of a Medici prince, were at least somewhat inclined to support a troublesome monk who made a case for keeping German gold in German pockets.
But how much money are we talking about, here? How much cash had to cross the mountains before the situation became intolerable to those in power? How much were the indulgences actually worth?
It's hard to say, but we can at least begin to estimate.
Tetzel was working for Albrecht of Brandenburg, a prince and bishop who needed money to pay off a massive loan to the House of Fugger. Albrecht had taken out the loan in order to pay Pope Leo X for the archiepiscopate of Mainz. The sale of the archiepiscopate was big business, which like most big deals required financing. The financing model was that the pope would license a campaign to sell indulgences in Albrecht's territory, and that the profits would be divided evenly between Leo himself and Albrecht, who would pay the Fuggers.
Ultimately, of course, this means that the plan was for the indulgences to bring in double the cost of Albrecht's loan. So the critical question is: How much had Albrecht borrowed?
This information is not readily available, but that doesn't mean it is unavailable. Ludwig Freiherr von pastor's History of the Popes, vol. 7, p. 331 (in the English edition) says that the see of Mainz cost Albrecht 14,000 ducats, and then another 10,000 ducats of "extraordinary fees" for the privilege of occupying not only Mainz but also the sees of Magdeburg and Halberstadt. He cites Albrecht's "bond for 29,000 Rhehish gulden" in Aloys Schulte's 1904 Die Fugger in Rom 1495-1523.
So, assuming he had borrowed the entire cost of his new position, Albrecht owed 24,000 ducats or, perhaps, 29,000 Rhenish gulden. Nice to know, but as Americans often ask when traveling, "How much is that in real money?"
Marc Carlson is a librarian at the University of Tulsa and, apparently, a man fascinated by vast quantities of random information. Although he admits it is very, very rough, he presents a table estimating the approximate value of various ancient and medieval currencies. According to Carlson, both a ducat and a gulder, in 16th-century Germany, were worth approximately $500 in money circa the year 2000.
So, whipping out our calculators, we find that Albrecht borrowed between $12 million and $14.5 million to finance his ecclesiastical ambitions. In which case, Tetzel was apparently expected to bring in between $24 and 30 million.
That's a lot of money, to be sure, especially for one guy with a wagon and some cheaply-printed sheets of paper. It is even more money when you consider that, if Luther was right, Tetzel had absolutely nothing to sell.
On the other hand, consider this. An historian named John James (see page 10 of Amy Denning's fascinating BA thesis) has devoted vast energy to estimating the construction costs of medieval French cathedrals, and comes in which a price tag of $548 million (in 2011 dollars) for Chartres. Barcelona's Sagrada Familia cathedral has been under construction for over a century, and is estimated to have cost $1.3 billion so far. A modern nuclear power plant costs several times as much.
So, yes, St. Peter's was expensive. But if its cost had been limited (as it was certainly not) to the value of Tetzel's indulgence campaign, it might have at least been a decent value.