This is the strongest proof the friends of Coster can present, and it has been thoroughly dissected by investigators representing both sides of the controversy. The weak points of the document appear to be:
(1) The date of the experiment with wood letters in the garden (about 1440) does not leave enough time for completion of the invention of separate metal types and the equipment of a large printing office until the theft which Junius says occurred in 1441.
(2) The date of the theft of 1441 does not reconcile itself with the fact that Gutenberg in 1436 was probably experimenting with his invention at Strassburg.
(3) The claim that a Dutch edition of the “Mirror of Salvation” was printed with separate types cut from wood seems doubtful, because even the best modern machinery has not demonstrated that wood type can be made as accurately as is necessary for arrangement of small types in a massed page. When it is considered that the size of types used on the edition mentioned was about fourteen point, and the lines were printed in alignment, the modern printer is sure to question the accuracy of the assertion.
Four editions, two in Latin and two in Dutch, of the “Mirror of Salvation,” are known to exist, all printed from types except twenty pages of the second edition, which are printed from engraved blocks. They are the work of some early printer of Holland; whether his name was Coster or whether the books were printed before or after 1450 will probably never be ascertained.
One Peter Scriverius in 1628 wrote a new version of the invention in which he says that “In the year 1428, Laurens Coster, then a sheriff of Haarlem, strolled into the Haarlem woods. He took up the branch of an oak-tree, cut a few letters in relief on the wood, and after a while wrapped them up in paper. He then fell asleep, but while he slept, rain descended and soaked the paper. Awakened by a clap of thunder, he took up the sheet, and to his astonishment discovered that the rain had transferred to it the impress of the letters,” etc.
Junius had placed the date of Coster’s invention at about 1440; Scriverius put it at 1428. The date was again changed, this time to 1420, by Marcus Boxhorn, who wrote on the subject in 1640.
In 1722 a statue of Coster was erected in Haarlem, but no date was placed upon it.
A “true and rational account of the invention” was published at Haarlem by one Leiz in 1742, which gives in detail the supposed events of Coster’s life as a printer, from the cutting of the wood letters on the tree bark in 1428 to his death in 1467, but does not reveal the source of information.
Gerard Meerman, a learned but impractical writer of Rotterdam, in 1765 published a book, “Origines Typographical,” and comes to the conclusion that typography was invented by Louwerijs Janszoon, known as Laurens Coster, who was sheriff at various times between 1422 and 1434, and who died between 1434 and 1440; he used separate wooden types about 1428 or 1430, and did not (as Junius had claimed) use lead or tin types; he was robbed on Christmas night 1440 by Johann Gensfleisch (elder brother of Johann Gutenberg), who carried the art to Mainz; he printed one edition of the “Mirror” from wooden types.