_Parchment_, also made from skins, was prepared by a different process than the tanning of leather. The word "parchment" comes from the name of the city of ancient Mysia--Pergamos or Pergamum--where its manufacture was originated and was carried on for centuries. Parchment, though known for centuries before the Christian Era, was used by the Greek and Roman writers to only a limited extent for a period of some centuries, owing to their continued preference for the papyrus production. The more general use of parchment was finally accelerated by necessity, and on this wise: Ptolemy Philadelphus (prompted perhaps by envy for the growing literary achievements of the kings of Pergamos and by jealousy for the supremacy of Alexandria) laid an embargo upon the exportation of the papyrus, then exclusively produced in Egypt. This restriction necessitated and accelerated the manufacture of parchment and thus stimulated its use, though papyrus continued to be, until after the beginning of the Christian Era, the more common and the cheaper though less durable material for receiving and perpetuating literature. Parchment is not only one of the earliest--and the very best--but next to the baked tablets, the most durable material for all written productions. The employment of parchment to record and preserve literature spread from Pergamos throughout Europe and, because of its superior quality and its greater durability, came into the preëminence which it held until the invention of paper. Most of the existing manuscripts of a greater age than the sixth century are written on parchment. Indeed, its use for important and valuable documents, as embossed records and resolutions of respect, and diplomas and the like, has survived unto the present time. _Vellum_ is the designation for a finer quality of writing material made from calf skins or skins of antelopes. Some of the oldest, best, and clearest of the existing copies of the Bible--notably, the Vatican and the Sinaitic manuscripts--are written on vellum.