Structure

The skins of a range of animals were used, depending on the size and quality required.: for a small fine manuscript, the foetus of a calf might be used, yielding a skin as fine as tissue paper. Pigskin was unsuitable, because the bristles had such large follicles the skin would be heavily pitted.

Large books such as this Antiphonal (570 x 395 mm), which has 360 pages, or 180 sheets of vellum folded in half, must have required a whole skin from an animal the size of a young steer. The sheet of vellum would have been folded in half, with the rougher, more yellow side on the outside, the folded sheets tucked inside each other like a newspaper, and then sewn together down the central fold. Each group of such sheets is called a gathering, and this Antiphonal has four sheets to a gathering, making eight pages. The gatherings were then stacked on top of each other, and all sewn together, using the initial stitches through the centre fold of the gathering as a foundation for the second stage of sewing.

To protect the codex, as this text block of pages was first called, wooden boards were attached back and front by cords which had been integrated into the sewing structure. The cords were inserted into holes in the boards and fixed with wooden pegs, and the manuscript then had an outer protective covering, which was quite often augmented by metal studs. A medium as firm and heavy as wood was necessary to keep the vellum text block in shape, because skin flexes and shifts with changes in temperature and humidity. We still call the covers of a book the boards, despite the fact that for over three centuries now cardboard has been used instead.

To create a huge manuscript such as the Antiphonal in this way was a big commitment on the part of a monastic community. It is most unlikely that a monastery would have sufficient resources within the community to supply the skins, so the vellum would have had to be bought in. It may have been gradually accumulated over many years.