Catholicon (1286)

Mosley suggests that the book may have been printed using metal types wired together in two-line units.

[2] Paul Needham has presented the revolutionary theory that the Catholicon was printed by means of two-line stereotypes or "slugs", a technology not documented in any form until after 1700.

The colophon of the book (in Latin) refers to the technology used: "With the help of the Most High ... this noble book Catholicon has been printed and accomplished without the help of reed, stylus or pen but by the wondrous agreement, proportion and harmony of punches and types, in the year of our Lord's incarnation 1460 in the noble city of Mainz of the renowned German nation ...".

S. H. Steinberg in his book Five Hundred Years of Printing (1955) makes these observations "the type is about a third smaller than that of the 42-line Bible; it is considerably more economical and thus marks an important step towards varying as well as cheapening book-production by the careful choice of type"; "the book contains a colophon which it is difficult to believe to have been written by anybody but the inventor of printing himself".

[3] A summary of the problem is to be found in (only in German): Andreas Venzke: Johannes Gutenberg – Der Erfinder des Buchdrucks und seine Zeit.