Bibliothèque Nationale: For lack of space, Colbert had some of the books transported to two houses he owned in Vivienne Street, and in two hotels belonging to Mazzarin, where Mansart built two galleries parallel to Richelieu Street (the present day Mansart and Manzarine Galleries.) Opened to scientists in 1720, the library continued to expand and catalogs were established. In 1724, the books were all transferred to the present site, and the architect, Robert de Cotte expanded the two Mansart Galleries. Only the central façade in the courtyard of honor remains. At the end of the 18th century, the financial difficulties of the Old Regime prevented any expansion of the library. The Revolution produced a great number of books; the libraries of nobles and of convents were confiscated and the legal registration procedure reinforced. 40,000 works enter the National Library in this manner, each year. New printing technologies also allow a much greater production of books today.