The most interesting edifice in the Rue Richelieu is the Library, called, according to the existing form of Government, Royal, National, or Imperial. Its original title was King's Library (Bibliothèque du Roi), and it has been suggested that, to avoid the frequent changes of name to which the instability of things in France seems to expose this valuable institution, it should be called, once for all, Bibliothèque de France. The nucleus of the National Library, with its innumerable volumes, was formed by Charles V., and received considerable additions, considerable at least for the time, when books were scarce, from Louis XI. Under the reign of the latter sovereign so much value was attached to books of a rare character that, to obtain the loan of a certain volume written by the Arabian physician Rhazes, the king had to furnish security, and bind himself by the most solemn obligations to return it. According to Dulaure, this pious monarch had but a poor reputation for returning books, combined with an eagerness for getting them into his possession. "In 1472," says the author of "The History of Paris" and of the "Singularités Historiques," "Hermann Von Stathoen came from Mayence to Paris entrusted by the famous printers Scheffer and Hanequis to sell a certain number of printed books. While at Paris he was attacked by fever and died. In virtue of the _droit d'aubain_ the king's officers took possession of the books and money of the defunct, sending the latter to the king's exchequer and the former to the king's library. This proceeding was by no means to the taste of Scheffer and Hanequis, who complained to the emperor, and obtained from him letters addressed to Louis XI. in which the French king was invited to restore both books and money. Louis XI. admitted the justice of the claim, and on the twenty-first of April, 1475, issued Letters Patent in these terms: 'Desiring to treat favourably the subjects (Scheffer and Hanequis) of the Archbishop of Mayence, and having regard to the trouble and labour which the persons in question have had in connection with the art and craft of printing, and to the profit and utility derived from it, both for the public good and for the increase of learning; and considering that the value and estimation of the said books and other property which have come to our knowledge do not amount to more than 2,425 crowns and three sous, at which the claimants have valued them, we have for the above considerations and others liberally condescended to cause the said sum of 2,425 crowns and three sous to be restored to the said Conrad Hanequis.'" Dulaure, after citing this letter, adds that the restitution was made in such a manner that the printers received every year from the King's Treasury a mere driblet of 800 livres, or francs, until the entire sum had been repaid.