Consisting of two interconnected ogival
shells, the cathedral's octagonal dome was erected between 1418 and 1434 to a
design which Filippo Brunelleschi entered in a competition in 1418 but which
was only accepted, after much controversy, in 1420.
A masterpiece capable of withstanding
lightning, earthquakes and the passage of time, it continues to enchant all
those who observe it from afar. The dome
has a diameter of 45.5 metres, the equivalent of the baptistry in its entirety.
The competition that the Opera di Santa
Maria del Fiore ran in 1418 was won by Brunelleschi, but work did not get under
way until two years later and was not completed until 1434.
The cathedral of Florence was consecrated
by Pope Eugene IV on 25 March 1436.
Brunelleschi's astonishingly innovative
approach involved vaulting the dome space without any scaffolding by using a
double shell with a space in between. The
inner shell (with a thickness of more than two metres) is made of light bricks
set in a herringbone pattern and is the self-supporting structural element
while the outer dome simply serves as a heavier, wind-resistant covering. The dome is crowned by a lantern with a
conical roof, designed by Brunelleschi but only built after his death in 1446,
while the gilt copper sphere and cross on top of the lantern, containing holy
relics, was designed by Andrea del Verrocchio and installed in 1466.
The inner shell of the dome was frescoed
by Giorgio Vasari and Federico Zuccari from 1572 to 1579, the subject matter
chosen, namely the Last Judgement,
reflecting the iconography adopted in the baptistry. The frescoes on the inner shell of the dome
were the object of a thorough restoration between 1978 and 1994.