The issue of letters of indulgence was a very common practice in the Catholic Church just before the Reformation. After confessing or doing other godly work, the faithful received a decree exempting them from punishment for their sins. Letters of indulgence were bought en masse on certain occasions. As such, Pope Nicholas V. issued a ‘complete indulgence’ in 1451 and used the money he collected for these to finance the war against the Turks. The Mainz letters of indulgence, which were produced following that in 1454/1455 around the same time as the invention of printing, are among the earliest documents ever printed. A space was left free in the type area to enter the name of the issuer of indulgence and the sinner as well as the current date, and so such letters of indulgence can be seen as the first ever printed forms. Johannes Gutenberg was also supposed to have produced such relatively simple broadsheets before or parallel to printing the Gutenberg Bible. In the 15th and 16th centuries, huge quantities of them were printed, some of them with graphic illustrations.

The well-known preacher Johann Tetzel stood for the institutionalised trading in indulgences in Central Germany from 1516 as the sub-commissioner and later general sub-commissioner for the bishopric of Meissen. By selling letters of indulgence for charitable acts en masse, the Catholic Church partially financed the building of the new St. Peter’s Basilica, the foundation stone of which was laid in 1506. Furthermore, the local sovereign and the preacher issuing the indulgence also profited from the sale. Martin Luther sharply criticised trading in indulgences. It was more than anything else this questionable practice of absolution, which was far removed from God and yet permitted by Church law, that prompted Luther to write his 95 theses. These brought in a radical reform of the Church and even the Catholic Church later banned trading in indulgences and threatened those who dealt in them with ex-communication from 1570 onwards.