Embedded into the grey paving stones of the Piazza del Duomo, a few metres beyond the east end of the cathedral, is a large circular slab of white marble. However, the marble has no inscription to explain why it is there!
The explanation lies in an event which took place one stormy winter's night in the month of January 1601. While a thunderstorm was raging over the city, lightning struck the lantern, the twenty-metre high structure, which sits atop the cathedral's dome. The gilded copper orb and cross, which crowns the lantern, came crashing to the ground along with large chunks of the lantern itself.
The orb had been added to the cathedral in 1468 by Andrea del Verrocchio. This was no mean feat, given that it is 2.5 metres wide, weighs two tons and had to be hoisted to a height of 107 metres (350 feet).
The Grand Duke Ferdinando I entrusted the reconstruction of the lantern to Alessandro Allori, Bernardo Buontalenti and Gherardo Mechini, specifying that it was to be rebuilt exactly as it was before.
The lantern was duly repaired and the orb and cross were replaced on October 21st 1602. The spot where they had hit the ground was marked by the white marble disc that we see today. However, for some reason, no inscription was added.