The Greeks developed parchment in 600 BC. Papyrus, which was made of reeds, had been used in Egypt from as early as 2450 BC, but bigger sheets could be made of parchment and it could be written on both sides. It could also be stitched into books, whereas papyrus could only be collected in loose sheets.

Parchment is made of sheepskin, and finer-quality vellum parchment of calf or goatskin. Its complicated manufacture means that it is usually reserved for important documents.

Magna Carta was handwritten by royal scribes in Latin, the language of government and record in King John's England. The scribes wrote the charter with quill pens on sheets of parchment – which is of unknown origin - because parchment was very expensive to produce, the scribes used a small script and abbreviated the Latin text to save space.

Each of the surviving copies of Magna Carta is a different size and shape, and each has minor textual variations, but none is more authoritative than the others.

Take one sheep…

The process required a fair amount of skill: after the sheep was killed, the shorn and washed sheepskin was laid fleece-side down in water for 24 hours.

The sheepskin was then rinsed and soaked in a lime bath for around three days, which made the fleece fall out, and helped remove grease from the skin.

It was then rinsed again and any remaining hairs removed with a knife. Sometimes it had another lime bath dip and rinse before being stretched on a wooden frame. Next came the most skilled part of the process: removing the flesh from the pelt with a sharp, rounded knife called a strickle (one slip of the hand and it would be ruined).

After being degreased with chalk, the skin was smoothed with fine sand or powdered limestone, then left to dry on the stretcher before being cut to size.

Little scraps were used by novice quill-handlers and for the spines of books, while large books required hundreds of skins. Vellum is made in exactly the same way.

Its use today

Vellum is still made for calligraphy, the best quality being Manuscript vellum, but parchment is less common because of its higher grease content. It is still used for copies of Acts of Parliament. In 1999 MPs narrowly voted against ending this centuries-old tradition - a surprise result which was greeted by loud cheers and waving of Order Papers.

Opposition was led by Labour's Brian White (Milton Keynes NE) who said ending the tradition - which dates back to 1497 - would put 12 people out of work in his constituency and mean the death of the industry in Britain. Newport Pagnell in Buckinghamshire is the only place in England where parchment, and vellum, are still made - by William Cowley & Co. in Caldecote Street.