The original Astrarium disappeared sometime after 1530 (likely melted down for scrap metal or lost during the Sack of Rome in 1527). Our knowledge comes entirely from Dondi’s own illustrated manuscript.
Giovanni Dondi dell'Orologio's Astrarium is considered one of the most intricate and complex mechanical clocks ever created. The Astrarium, built around 1364, was an astronomical clock that not only displayed the time but also showed the positions of the sun, moon, and stars. built around 1364