In the autumn of 1516 Michelangelo received from Leone X the prestigious commision for the realization of the facade of San Lorenzo. The several phases of design are demonstrated by three Casa Buonarroti’s drawing (45 A, 47 A e 43 E) which reveals the development of Michelangelo’s ideas. This sheet shows the third and final project, carried out in February 1517, which arguably was subsequently translated in the wooden model still preserved in Casa Buonarroti.