In a previous business partnership, he suffered a loss.

During the 15th century, a shrine called Aachen was located 160 kilometers northwest of Strasbourg city. In the year 1439, an event was planned for this revered site. The pilgrims believed that if they could catch the reflection of Aachen in a mirror, they would be able to capture the healing qualities, therefore the event was expected to draw a big crowd.

An interesting fact about Johannes Gutenberg is that he forged agreements with investors to benefit from the production of convex mirrors for pilgrims. Due to flooding and the emergence of sickness, the event had to be postponed. This situation caused him trouble because investors demanded their money. He expressed his idea for inventing the mechanical movable type printing technique on this occasion.