By progressive improvements, especially in the hands of the Roman artists, this Egyptian paper was brought to a high degree of perfection. In later ages it was manufactured of considerable thickness, perfect whiteness, and an entire continuity and smoothness of surface. It was, however, at the best, so friable that when durability was required the copyists inserted a page of parchment between every five or six pages of the papyrus. Thus the firmness of the one substance defended the brittleness of the other; and great numbers of books so constituted have resisted the accidents and decays of twelve centuries.
Three hundred years before the Christian era the commerce in this article had extended over most parts of the civilized world; and long afterwards it continued to be a principal source of wealth to the Egyptians. But at length the invention of another manufacture, and the interruption of commerce occasioned by the possession of Egypt by the Saracens, banished the paper of Egypt from common use. Comparatively few manuscripts on this material are found of later date than the eighth or ninth century; though it continued to be occasionally used long afterwards.
The charta bombycina or cotton paper, often improperly called silk paper, was unquestionably manufactured in the east as early as the ninth century, possibly much earlier; and in the tenth it came into general use throughout Europe. This invention, not long afterwards, became still more available for general purposes by the substitution of old linen or cotton rags for the raw material; by which means both the price of the article was reduced, and the quality improved. The cotton paper manufactured in the ancient mode is still used in the east, and is a beautiful fabric.
From this brief account of the materials successively employed for books, it will be obvious, that a knowledge of the changes which these several manufactures underwent will often serve, especially when employed in subservience to other evidence, to ascertain the age of manuscripts; or at least to furnish the means of detecting fabricated documents.
The preservation of books, framed as they are of materials so destructible, through a period of twelve, or even fifteen hundred years, is a fact which might seem almost incredible; especially as the decay of apparently more durable substances within a much shorter period, is continually presented to our notice. The massive walls of the monasteries of the middle ages are often seen prostrate, and fast mingling with the soil; while manuscripts penned within them, or perhaps when their stones were yet in the quarry, are still fair and perfect, glittering with their gold and silver, their cerulean and cinnabar.
But the materials of books, though destructible, are so far from being in themselves perishable that, while defended from positive injuries, they appear to suffer scarcely at all from any intrinsic principle of decay, or to be liable to any perceptible process of decomposition. "No one," says Father Mabillon,[5] "unless totally unacquainted with what relates to antiquity, can call in question the great durability of parchments; since there are extant innumerable books, written on that material, in the seventh and sixth centuries; and some of a still more remote antiquity, by which all doubt on that subject might be removed. It may suffice here to mention the Virgil of the Vatican Library, which appears to be of more ancient date than the fourth century; and another in the King's Library little less ancient; also the Prudentius, in the same library, of equal age; to which you may add several, already mentioned, as the Psalter of S. Germanus, the book of the councils, and others, which are all of parchment. Many other instances I might name if it were proper to dwell upon a matter so well known to every one who is acquainted with antiquity.
"The paper of Egypt, being more frail and brittle, may seem to be open to greater doubt; yet there are not wanting books of great antiquity, by which its durability may be established. To go no further, there is in the Royal Library a very old codex written upon the philyra (or bark of the linden tree) containing the homilies of Avitus, I mean the copy from which the celebrated Jac. Sirmundus prepared his edition; we have also seen two other codices of the same material in the Petavian Library, containing some sermons of S. Augustine, which, in the opinion of the learned, are about 1100 years old. Of the same kind is that rare and very ancient codex in the Ambrosian Library, mutilated indeed, but consisting of many leaves of Egyptian paper, which contain some portions of the Jewish history of Josephus. These examples are sufficient to demonstrate the durability of the Egyptian paper in ancient books." The author then goes on to mention several instances of deeds and chartas written upon the paper of Egypt, still extant, though executed in the fourth and fifth centuries.
Books have owed their conservation, not merely to the durability of the material of which they were formed, but to the peculiarity of their being at once precious, and yet not (in periods of general ignorance) marketable articles; of inestimable value to a few, and absolutely worthless in the opinion of the multitude. They were also often indebted for their preservation in periods of disorder and violence to the sacredness of the roofs under which they were lodged.—Taylor's History of the Transmission of Ancient Books to Modern Times.