Page:De Vinne, Invention of Printing (1876).djvu/447

Rh a quarto of 20 leaves. It is possible, but not certain, that Gutenberg printed these books. A Treatise on Reason and Conscience, by Matthew of Cracow, a small quarto of 22 leaves, and A Summary of the Articles of Faith, by Thomas Aquinas, a quarto of 12 leaves, printed in the types of the Catholicon, may be confidently accepted as the work of Gutenberg. But one copy or fragment of some of these works is known. Gutenberg may have printed many other works which have been destroyed and forgotten. The existing copies or fragments of pamphlets and books printed before 1462 are enough to prove that printing met