All this precaution, of course, is testimony to the great value of books at this period. It is true that the labor of the monks was not paid but they had to be supported while at their work and owing to the time taken to write, or rather paint, a manuscript, for it was really rather painting than writing, this was no small item. The materials used were also expensive. Parchment was costly and tended to become more so as the increase of literary activity and the multiplication of books increased the demand for it. Considerable expense was also involved in the colored inks and especially in the gold which was used so lavishly in the decorations. Monasteries and rich men regarded manuscripts as among their chiefest treasures. Special provision was made for the purchase of materials and the maintenance of the monastery libraries. The name of the generous benefactor who gave a book or, more commonly, the material for one, was inscribed in the book, often with a request for the prayers of the reader, and was borne upon the honorable roll of the benefactors of the house. Large sums of money and even estates were given for choice manuscripts and manuscripts were considered worthy gifts for kings. We have a record of the 12th century in England of fifty marks being paid for a Bible. This sum of money, taking into account the very great difference in purchasing power, would represent at least $3000 of the money of to-day. As time went on enlightened kings like Alfred of England and the Emperor Charlemagne patronized and forwarded learning. Laymen, particularly kings and great nobles, began to collect libraries of their own. The National Library of France was begun by King John, who reigned from 1350 to 1364, who started it with twenty volumes. His son Charles V brought the number up to 900. It contained books on devotion, astrology, law, medicine, history, and a few classics.