Developed in Pergammum (180 BC) when the king was refused any more Papyrus from Egypt to build his library. So he developed a new type of writing material through a new process for the treatment of skins. This was called vellum or parchment. From the skin of sheep or goats a fine quality of leather was specially and carefully prepared for writing on both sides. Most of the known manuscripts are on vellum. Later they were glued into book form, this was called a Codex. The codex made it possible to have much more Scripture in one place.