Principio con testimone (Beginning with Witness) . In the most sacred hall of the synagogue, with the vestiges of the altar that once contained the Books, Caravaggio places his Principio on the ground in proximity to the remains of the columns. A thin slab of bronze with the geometrized form of the artist's hand is covered by a cast of the earth on which as small child has taken his first steps. On top of the latter rest spheres of different materials and forms, similar to planets in a mysterious landscape. From this position the spheres are launched into the surrounding space, leaving visible traces on the slabs that, similar to ruins, have been distributed by Caravaggio around the perimeter of the hall. After colliding, the balls bounce back and can be re-placed in their original position to begin new expansions. The witness , an organic form in aluminium, marked with holes and trajectories, is the "first of the testimonials" and, as such, not subject to variation.