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 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.