Letter of Indulgence

A letter of indulgence was a printed or handwritten document issued by the Catholic Church. It could be acquired in exchange for money. It promised the buyer that part of the punishment for their sins would be remitted. This did not mean punishment before a secular court, but rather a period of penance in the afterlife, in which people at the time firmly believed. These letters were sold in large numbers especially in the 15th and early 16th centuries. Today the term is mostly used figuratively, when someone buys their way out of guilt instead of changing their behavior.

The dispute that became the Reformation

The trade in letters of indulgence was an enormous business for the Church. The proceeds were used, among other things, to finance the rebuilding of St. Peter’s Basilica in Rome. Preachers traveled through the towns aggressively promoting the purchase. A well-known advertising slogan from that time roughly translates as: As soon as the coin rings in the box, the soul springs free from the fire.

It was precisely this that sparked opposition. In 1517, the monk Martin Luther published his 95 Theses, in which he sharply attacked the indulgence trade. His main argument: forgiveness cannot be bought, but is a matter for God alone. Out of this dispute grew the Reformation, and with it the split of Western Christianity into a Catholic and a Protestant Church.

Without this conflict, Europe would look different today. It changed maps, wars, and power structures for centuries. That is why the letter of indulgence appears in almost every history book. It is an example of how a financing model can shake an entire institution to its core.

What was written on the paper and what it cost

The Church distinguished between guilt and punishment. Guilt was forgiven through confession, for which no indulgence was needed. What remained, however, according to the teaching of the time, was a temporal punishment that had to be atoned for in what was called purgatory. An indulgence shortened this time. Originally, it was obtained through prayers, pilgrimages, or alms.

Later, money took the place of these acts. The printing press made distribution easy: forms were printed in large numbers, and only the buyer’s name had to be filled in by hand. Prices were tiered according to income — a wealthy merchant paid considerably more than a craftsman. Distribution and accounting sometimes ran through banking houses, which kept a share for themselves.

A common misconception is that a letter of indulgence granted permission for future sins. That was officially never the intention. In practice, however, many buyers understood it exactly that way, and some preachers hardly contradicted this. This gap between doctrine and sales practice was at the core of the scandal.

Why the term appears in economic texts

Historical letters of indulgence can be found today in museums and archives. In everyday life, however, the word is encountered almost exclusively as a comparison. When a newspaper writes about a modern indulgence trade, it refers to money meant to offset a wrongdoing without anything fundamental actually changing.

The comparison is most common in the context of climate protection. Anyone booking a flight can pay a few extra euros for climate protection projects, such as reforestation. Critics call this a letter of indulgence, because the flight still takes place regardless. A similar debate surrounds the trade in CO₂ certificates, in which companies buy and sell rights to emit greenhouse gases.

The image also appears in the tech industry. Large data centers for artificial intelligence consume a lot of electricity. When a corporation offsets this consumption on paper by purchasing green electricity certificates, critics speak of a letter of indulgence. The accusation then is: the balance sheet checks out, but the actual consumption remains. Whether the comparison is fair depends on how effective the funded projects really are.