The dimensions or sizes of our books at the present day have their origin in the sizes of the parchment in olden times. The entire skin of the animal, cut square and folded in two, represented the “in-folio,” which, moreover, varied in length and breadth; and we have every reason to suppose that paper, from the day it was invented, followed the ordinary sizes of the folded parchment. As to the dimensions of the parchment employed for diplomas, they varied according to the time, the brevity of the matter, or the nature of its employment. Among the ancients, who wrote only on one side of the parchment, the skins were cut in bands joined together so as to form _volumes_ or rolls, which were unrolled as their contents were read. This custom was preserved for public and judicial acts for a long time after the invention of the square book (_codex_) had caused the _opisthographic_ writing to be adopted, by which is to be understood writing on both sides of the page. In principle, only the final formulæ, or the signatures, were written on the back of the document. By degrees people adopted the practice of writing on the back as well as the front of the page; but it was not till the sixteenth century that this custom became general. [Illustration: Fig. 331.--Seal of the King of La Basoche. (This title was suppressed, with all its prerogatives, by Henry III.)] Judicial acts, composed sometimes of many skins sewed together, came in time to form rolls of twenty feet in length; to such extreme proportions did they reach, though at first they were so small in size that their limited dimensions are truly incredible; for in 1233 and 1252 we find contracts of sales of two inches long by five inches wide, and in 1258 a will written on a piece of parchment of two inches by three and a half. It was by way of compensating for the great cost of parchment that opisthographic writing was adopted and rolls were put aside; and the name alone remains as applied to the _rolls_ of procedure. The size that leaves should assume was also fixed, according to the different uses for which they were intended. For instance, the leaves of parliamentary documents were nine inches and a half long by seven and a half wide; those of the council, ten by eight; those of finance and of private contracts, twelve and a half by nine and a half; letters of pardon, under the king’s hand, were to be on entire skins squared, two feet two inches by one foot eight inches in diameter. [Illustration: Fig. 332.--The Paper-Maker, drawn and engraved in the Sixteenth Century by J. Amman.]