PARCHMENT
the processed skins of certain animals--chiefly sheep, goats, and calves--that have been prepared for the purpose of writing on them. The name apparently derives from the ancient Greek city of Pergamum (modern Bergama, Turkey), where parchment is said to have been invented in the 2nd century BC. Skins had been used for writing material even earlier, but a new, more thorough method of cleaning, stretching, and scraping made possible the use of both sides of a manuscript leaf, leading to the supplanting of the rolled manuscript by the bound book (codex).
Parchment made from the more delicate skins of calf or kid or from stillborn or newly born calf or lamb came to be called vellum, a term that was broadened in its usage to include any especially fine parchment. The vellum of most early manuscripts, through the 6th century AD, is of good quality. After this, as demand increased, a great amount of inferior material came on the market, but by the 12th century, when large numbers of manuscripts were being produced in western Europe, a soft, pliant vellum was in vogue. In Constantinople, a sumptuous form was produced at an early date by dyeing the material a rich purple and lettering it in silver and gold, a practice condemned as a useless luxury in a well-known passage of St. Jerome. The purple dye was subsequently abandoned, but the practice of "illuminating" parchment manuscripts in gold, silver, and other tints flourished throughout the European Middle Ages.
In modern usage, the terms parchment and vellum may be applied to a type of paper of high quality made chiefly from wood pulp and rags and frequently having a special finish.