Units of paper quantity and US measure, in some sources, a quire was originally 24 sheets.) Quires of 15, 18 or 20 sheets have also been used, depending on the type of paper. The current word "quire" derives from OE "quair" or "guaer", from OF "quayer", "cayer", (cf. modern Fr. "cahier"), from L. "quaternum", "by fours", "fourfold". Later, when bookmaking switched to using paper and it became possible to easily stitch 5 to 7 sheets at a time, the association of "quaire" with "four" was quickly lost. In the Middle Ages, a quire (also called a "gathering") was most often formed of 4 folded
Book of Kells sewn together to form gatherings called quires. On occasion, a folio is not part of a bifolio but is instead a single sheet inserted within a quire. The extant folios are gathered into 38 quires. There are between four and twelve folios (two to six bifolios) per quire; the folios are commonly, but not invariably, bound in groups of ten. Some folios are single sheets, as is frequently the case with the important decorated pages. The folios had lines drawn for the text, sometimes on both sides, after the bifolios were folded. Prick marks and guide lines can still be