The Philatelic and Numismatic Office of the Vatican City celebrates the sixth centenary of Filippo Brunelleschi’s design of the dome of the cathedral of Florence, Italy, Santa Maria del Fiore. The dome is considered one of the most important Renaissance constructions. Consisting of two interconnected ogival shells, the octagonal dome was built between 1418 and 1436 (except for the lantern) according to a design the Florentine architect presented during a competition in 1418. On 25 March 1436 the Florentine cathedral was consecrated by Pope Eugene IV. Brunelleschi’s very innovative approach involved vaulting the dome space without using scaffolding and creating a double shell with a space in between. The inner shell (more than two meters thick) has a structural role, since it is self-supporting, while the outer dome serves simply as a cover. The dome is crowned by a lantern with a conical roof, designed by Brunelleschi, but built after his death in 1446. The gilt copper sphere and cross on top of the lantern, contains holy relics and was designed by Andrea del Verrocchio and installed in 1466. From the architectural point of view the construction of the dome of Santa Maria del Fiore represents the event that marked the beginning of the Renaissance, with the rediscovery building techniques of the classical era and the reorganization of the building site with the separation of the roles of designer and builder. Brunelleschi used innovative equipment that he himself designed for constructing the dome. The organization of the building site and the availability of equipment capable of moving heavy weights and raising them to great heights played a decisive role in the construction of the dome.