The presence of this rare example of a night clock refers to the singular episode concerning its conception. Pope Alexander VII (1655-1667), who suffered from insomnia and could not stand the ticking of the clock in his bedroom, commissioned the Campani brothers to make a silent and legible clock even in the middle of the night thanks to the creation of a openwork dial which was illuminated at the rear by a small oil lamp or a candle. Having completed a first prototype in 1656, Pietro Tommaso Campani took it to the pope to show it to him, and such was the satisfaction with the invention that he granted him a patent. Generally the clock was dark in color, made of ebony or other ebonized woods, in some cases, for the most important creations, it was decorated with polychrome inserts of hard stone. The altar structure culminated with a pediment flanked by volutes and featured a central copper front panel, often painted with subjects of inspiration alluding to the passage of time and life or religious. The latter was frequently surrounded by decorative columns or pilasters.