The project carried out by Michelangelo was one of the most significant examples of the transition from the Renaissance to architectural Mannerism, thanks above all to the treatment of the walls of the riccetto or entrance hall to the library. Carried out with classical elements, which as ornament gave an extraordinary monumentality to the space prior to the entrance to the reading room. The paired columns, decorative corbels, triangular and curved pediments... and other architectural elements that are found on the wall without any structural support function, fulfill a decorative function of sculptural architecture. This is completed with the coffered vault on pendentives at the top, and the outstanding monumental access staircase.
The rest of the library's rooms remained unused for a long time because Michelangelo left Florence in 1534, never to return. The walls of the reading room, as well as the roof, were also finished, but the ornamentation of the ceiling, the paved floor, the carving of the tables remained to be executed... with the anteroom not being completed until well into the 19th century, despite the fact that The building was inaugurated in 1571, forty-two years after the original commission.