There were accounts of scribes working in a similar manner in comparison to their rival printers, though the process was still subtly different. The pages on sheets of vellum were folded together to form a quire before the invention of printing or paper, and printed books also bound multiple quires to form a codex. They were simply made of paper. Manuscripts were also used as exemplars for printed books. Lines were counted off based on the exemplar and marked in advance, while the typesetting reflected the layout of the manuscript's text. Within a few generations, however, printed books were used as new exemplars. This process created various "family trees", as many printed sources would be double checked against earlier manuscripts if the quality was deemed too low. This necessitated the creation of stemma, or lines of descent among books. This made manuscripts gain a new significance, as sources to find earlier authority or a better authority, in comparison to the published version of a text. Erasmus, for instance, attained authoritative manuscripts from the medieval period due to his dissatisfaction with printed Bibles.