[Illustration: Fig. 392.--Fac-simile of the Twenty-eighth Xylographic Page of the “Biblia Pauperum;” representing, with Texts taken from the Old Testament, David slaying Goliath, and Christ causing the Souls of the Patriarchs and Prophets to come out of Purgatory.] had appeared in the Low Countries before the period assigned to the discovery of printing in Holland. Some of these were evidently xylographic, others show signs of having been printed with movable type of wood, not of metal. All have engravings of the same character as those of the “Speculum,” especially the “Biblia Pauperum” (“Poor Men’s Bible”) (Fig. 392), the “Ars Moriendi” (“The Art of Dying”) (Fig. 393) the “Ars Memorandi” (“The Art of Remembering”), which had a very wide circulation. However this may be, Laurent Coster, notwithstanding the progress he had made with his invention, was certainly ignorant of its importance. In those days the only libraries were those belonging to convents and to a few nobles of literary acquirements; private individuals, with the exception of some learned men who were richer than their fellows, possessed no books at all. The copyists and illuminators by profession were employed exclusively in reproducing “Livres d’Heures” (prayer-books), and school books: the first were sumptuous volumes, objects of an industry quite exceptional; the second, destined for children, were always simply executed, and composed of a few leaves of strong paper or parchment. The pupils limited themselves to writing passages of their lessons from the dictation of their teachers; to the monks was assigned the task of transcribing, at full length, the sacred and profane authors. Coster could not even have thought of reproducing these works, the sale of which would have seemed to him impossible, and he at first fell back upon the “Specula,” religious books which addressed themselves to all the faithful, even to those who could not read, by means of the stories or illustrations (_images_) of which these books were composed; then he occupied himself with the “Donati,” which he reprinted many times from xylographic plates, if not with movable type, and for which he must have found a considerable demand. It was one of these “Donati” that, falling under the eyes of Gutenberg, revealed to him, according to the “Chronique de Cologne,” the secret of printing. This secret was kept faithfully for fifteen or twenty years by the workmen employed in his printing-house, who were not initiated into the mysteries of the new art till they had served a certain time of probation and apprenticeship: a terrible oath bound together those whom the master had considered worthy of entering into partnership with him; for on the preservation of the secret depended the prosperity or the ruin of the inventor and his coadjutors, since all printed books were then sold as manuscripts.