Faithful working replica of the planetary clock designed and built by Lorenzo della Volpaia in 1510 to the commission of Lorenzo de' Medici, now lost. The clock's dial was highly innovative in design, allowing the motions of all the planets to be seen at a glance for the first time. It showed the motions of Mercury, Venus, Mars, Jupiter and Saturn, the phases and age of the Moon, the mean motion and true position of the Sun. It also indicated the time (by striking the hour), the day and the month. The wheelwork, drawn by a single weight, operated with a verge escapement and a regulator ring.