COSTER, LAURENS. - Dutch from Haarlem (his real name was Janszoon), who lived in the middle of the
A Cologne Chronicle, by G. Koelkoff and published in 1499, records the testimony of Ulrich Zell, a pupil of Gutenberg, according to whom the master had profited for his invention from the technique used in Holland for printing certain Grammars of Donatus. This circumstance, linked with other clues contained in various Dutch chronicles, and supported by the publication of Hadrianus Junius's Batavia (1588), which relates a fantastic tale told by a servant of C., gave rise to a legend according to which the Dutchman, having carved some beechwood types for pleasure, had the idea of replacing them with lead ones, and with these printed various books, including a Speculum. But Gutenberg, having learned of his procedure at Aachen in 1440, allegedly stole the press and the types and transported them first to Cologne, then to Mainz.
The incredibility of certain elements, the absence of any reliable biographical data, the doubt that the Speculum itself—of which only a memory remains and which is known to have had leaves printed on only one side (opisthographs)—might have been a xylographic book, lead us to consider the Costerian tradition as purely fantastic. Nor can it be affirmed that he was the first Dutch printer, and there has even been no lack of those who have outright questioned the existence of C. Unfortunately, the editions attributed to him lack colophons, and therefore nothing can be said about the place and date of their publication.