entering the space of sagrestia nuova, the gaze rests on the marble skilfully worked by michelangelo buonarroti and on the elegant architectural geometries in pietra serena. the medici tombs are brushed by natural light, descending from the lantern of the dome and touching every detail. michelangelo brings together in architecture leonardo da vinci's theories gathered in his 'trattato della pittura' on primary and secondary light, according to which 'the light is the splendour that comes from the things that shine, and it is divided into primary, the one that touches the body with direct rays, and secondary, the light that comes from around the primary, caused by the reflected rays'. the mastery with which michelangelo works the marble surfaces makes this space, of which he is both architect and sculptor, unique for the play of direct and reflected light from the lead-polished marble, between illume and ilsole. thereby, a system of secondary lights contributes to the lighting necessary to enjoy the architectural and sculptural rhythm. the lighting project derives from listening to the space, discovered and studied through a scientific survey of natural light on the day of the summer solstice and from the knowledge of leonardo's theories on primary and secondary light. mario nanni, bringing his lights very close to the sun, created an intense and uniform light, not dramatic, with sculptural and sensual shadows, perfectly integrated with the natural light thought by the artist.