Marking Midday With a Bang

Map

The Field Gun That Marks Midday

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Every day, at exactly 12 noon, a shot is fired from a field gun on the Janiculum Hill (Colle del Gianicolo). The practise, known as the Cannone del Mezzogiorno (Cannon of Midday), was established in 1847 by Pope Pius IX (r. 1846-78) to set a standard time for the ringing of the city's church bells.

The official sundial that marked noon was located in a small tower on top of the Collegio Romano, the Jesuit seminary. There was a tall poll on the roof of the adjacent church of Sant' Ignazio di Loyola, which could be seen from Castel Sant' Angelo, where the cannon was originally located. A few minutes before noon a sphere was raised to the top of the pole as a signal for the artillerymen to get ready. As soon as the sundial marked noon, the sphere was dropped and the cannon fired.
 
In August 1903, the cannon was transferred to Monte Mario hill. A few months later, on January 24th 1904, it was moved to its present location, where it has remained ever since.

The firing of the cannon was suspended in 1939, at the outset of the second world war, but resumed 20 years later on April 21st (Rome's birthday) 1959. 

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