The literary merit of the block-books was small, and their shabby mechanical execution made them contemptible. To readers accustomed to handle great books of tinted vellum, admirably written in letters that are yet as sharp and legible as modern types, these miserable little pamphlets on dingy paper, and with muddy letters, scarcely deserved the name of books. By the educated readers of the fifteenth century they [p251] were rated as literary rubbish. Professors in the universities looked on them with the same contemptuous spirit which men of letters afterward manifested toward early newspapers. The attempts of early printers to furnish these poor substitutes for books to common people, so far from receiving any encouragement from scholars, met with their disdainful neglect. There were, indeed, a few praiseworthy exceptions, but the scholarship of the middle ages took sides with rank, in upholding all the conventional distinctions of society. They wished illiterate people to understand that books were the right of the educated only.[127] The period in which block-books were printed cannot be fixed within exact limits. They did not go out of fashion when types were invented: the illustrated block-book _Opera Nova Contemplativa_, the Italian adaptation of the _Bible of the Poor_, was printed in Venice about 1512; but block-books of inferior merit were made after this date. Berjeau describes one, the _Innocentia Victrix_, probably engraved in China at the order of the Jesuits, which was printed in 1671. But these books are really the last specimens of a dying art; in the sixteenth century, they were practically obsolete. The period of their greatest popularity may be fixed between the years [p252] 1440 and 1475. As we approach the latter date, we find block-books containing the names and places of the printers. We see that they were made at Ulm, Nuremberg, and Augsburg,—the towns which have the earliest records of manufacturers of playing cards,—in the district in which old image prints like the _St. Christopher_ have been oftenest discovered. It is probable that block-books were printed in Southern Germany at or near the time when the _St. Christopher_ was printed, but we have no positive proof that any block-book was printed in 1423. The German book with earliest printed date is the _Chiromancy_, but its date of 1448 is not certainly the date of printing.