Fust was born to a burgher family of Mainz, traceable back to the early thirteenth century.
The name was written "Fust" until 1506, when Peter Schöffer, in dedicating the German translation of Livy to Maximilian I, Holy Roman Emperor, called his father-in-law "Faust."
Johann's brother Jacob, a goldsmith, was one of the burgomasters in 1462, when Mainz was stormed and sacked by the troops of Count Adolf II of Nassau, in the course of which he seems to have been killed (suggested by a document dated May 8, 1678).
[5] Whatever the truth, the Helmasperger [de] document of November 6, 1455, shows that Fust advanced money to Gutenberg (apparently 800 guilders in 1450, and another 800 in 1452) to carry on his work, and that Fust, in 1455, brought a suit against Gutenberg to recover the money he had lent, claiming 2026 guilders for principal and interest.
It appears that he had not paid in the 300 guilders a year which he had undertaken to furnish for expenses, wages, etc., and, according to Gutenberg, had said that he had no intention of claiming interest.
He also revealed in court that he had to borrow the money he gave to finance Gutenberg at 6% in order to even give the loan.
All in all, Gutenberg ended up having to pay 1,200 guilders to Fust along with all of the completed Bibles, unfinished books, and his workshop.
This meant that Schöffer would be able to use the same techniques he had learned and practiced, while the savvy businessman Fust could find ways to do what he was best at, which was to sell the books that they were making.
After several of Gutenberg’s bibles were sold to King Louis XI of France, it was decided that Fust was performing witchcraft.
It was also discovered that all of the letters in these bibles, presented to the King and his courtiers as hand-copied manuscripts, were oddly identical.
Parisians figured that the devil had something to do with the making of these copies, and Fust was thrown into jail on charges of black magic.
[9] He was eventually released, since it was proved he was running a business in which printing enabled the rapid production of multiple copies of the same text.
[citation needed] In 1464, Adolf II of Nassau appointed for the parish of St Quintin three Baumeisters (master-builders) who were to choose twelve chief parishioners as assistants for life.
He certainly was in Paris on July 4, when he gave Louis de Lavernade of the province of Forez, then chancellor of the duke of Bourbon and first president of the parliament of Toulouse, a copy of his second edition of Cicero, as appears from a note in Lavernade's own hand at the end of the book, which is now in the library of Geneva.