The mystery of how the medieval world made some of its finest books has at last been solved — after 700 years. New research is revealing the trade secrets of Europe’s very first largescale commercial publishing industry. Several generations before the widespread introduction of paper into Christian Europe, the continent’s craftsmen discovered a way of transforming animal skins into wafer-thin sheets for use as pages in medieval books. They succeeded in making animal skin “paper” that was just 1/15th (and sometimes even 1/18th) of a millimetre thick — and armed with this new technology they were able to mass produce the world’s first lightweight books — an estimated 20,000-30,000 handwritten Bibles.
They kept the tricks of their trade strictly under wraps — and, for the past 700 years, most historians and others have believed that 13th century ultra-fine parchment makers must have used the skins of rabbits, squirrels and new born, still born and even aborted calves to make their super-thin products. But now, 700 years after deteriorating economic conditions forced Europe’s craftsmen to stop producing super-thin parchment, scientists have discovered that they hardly ever used such young calves, let alone rabbits and squirrels, but instead developed a method of making skin from adult sheep, adult goats and young eight-week-old cattle look like the skins of newborn calves.
In a series of tests carried out by British scientists on 72 lightweight parchment Bibles, made in various areas of medieval Europe, the scientists have discovered that 68 per cent were made of calf skin (many from France and probably some from England), around six per cent from adult sheep (mainly from England) and 26 per cent from adult goats (mainly from Italy and southern France).