Libraries, as a building type, closely resembled museums and were often associated with them. Like museums, libraries found their architectural origins in the painting or book lined galleries, that were often attached to chateaux's. The bibliotheque sainte - Genevieve, built to designs by Henri Labrouste between 1843 and 1850, marked a turning point in the evolution of the library. As a student, Labrouste raised eyebrows with dispatches from Rome that the academy considered shamelessly impertinent, such as his attention to the technical and structural details of the ancient buildings he was studying, his social interpretations of their designs, and his frequent use of color in his recreations. In 1838 he was named architect for the reconstruction of the old Bibliotheques sainte - Genevieve, which was ill suited to the heavy use it was receiving. The funds for his venture was approved in 1843, after many studies of the old building.
The renovations were simple yet ingenious. The library was arranged on two floors. The reading room on the second floor, where it would receive more natural light. The books were arranged on the ground floor along the walls of the great hall. The need for fire prevention and general safety suggested the use of masonry and iron for the floors and metal supporters for the walls and roof. Labrouste's genius and ingenuity lay in exposing the cast iron structure of the vault of the reading room, which was supported around the perimeter by the side walls, composed of arcaded bays, and a row of eighteen slender metal columns that bisected the space. Labrouste did not make literal copies of the columns, opting instead for fluted shafts with composite capitals, in keeping with the Italian renaissance style of the exterior of the building. The twin barrel vaults are supported by a double series of semicircular transverse rows of columns. The arched ribs are articulated by iron filigree in a pattern of volutes and spiky tendrils.
One aspect of modern architecture is the exposure of the inner workings of a structure. The Bibliotheques sainte Genevieve was the first building in Paris to do this. Even before the Eiffel tower or the Crystal palace, Labrouste designed the interior of the library to be open, airy and spacious, but also to expose the very things which kept the building up. By exposing the cast iron supports, which held the ceiling in place, Labrouste was faced with yet another design problem. Yet this problem was aesthetic. Would the eighteen rows of columns be identical, as in the classic style of architecture? Once again, Labrouste chose the uncharted path, by designing eighteen different rows of colums. Thus the library was not only modern, in it's exposure of its structure, but it was aesthetically pleasing and modern also. Modern architecture relies on the concept of form following function, as was displayed in Labrouste's Bibliotheques sainte Genevieve. The aesthetic beauty of the library is only an extension of the structure of the building, which can be observed in both the etching and photo of the interior of the library (Top of page). The majestic rows of columns, and the open and airy feeling which the thin cast iron arches instill, come together to make the library not only the most functional building at the time, but one of the most simple and beautiful.