The room dedicated to the great scientist is the heart of the Museo Galileo. Here are displayed the only two surviving telescopes, among the many built by Galileo; the objective lens of the telescope through which, in January 1610, he observed the satellites of Jupiter for the first time; the military and geometric compasses he developed during his years in Padua; other instruments of his invention and educational models illustrating the crucially important results attained by Galileo in his studies on mechanics. At the centre of the room is the marble bust commissioned of the sculptor Carlo Marcellini by Cosimo III de' Medici. Some relics of Galileo, the secular saint of science, are also exhibited here: his thumb, the index finger and middle finger from his right hand, and a tooth, removed from Galileo's corpse when it was translated to the monumental tomb in Santa Croce.