The Cathedral or Duomo of Florence as we see it today is the end result of years of work that covered over six centuries of history. Its basic architectural project was designed by Arnolfo di Cambio at the end of the 13th century; the cupola that has made it a symbol for the whole of Tuscany was created by that genius of the Renaissance, Filippo Brunelleschi, while the facade that completed it was carried out as late as the late 19th century.

A whole series of structural and decorative interventions to both the exterior and the interior that were to enrich the history of the monument were carried out during this space of time: these range from the construction of the two sacristies to the 16th century marble flooring, and from the execution of the sculptures to the frescoes, signed by Paolo Uccello, Andrea del Castagno, Giorgio Vasari and Federico Zuccari (the Last Judgement in the cupola).

The third and last Florentine cathedral (the cathedral is always the church that is the seat of the bishopric), it was given the name of Santa Maria del Fiore (Holy Mary of the Flower) in 1412 in clear allusion to the lily symbol of the city. It was built on top of the second cathedral, which early Christian Florence had dedicated to Santa Reparata and which remained in activity for nine centuries, until orders were given to demolish it in 1375: considerable remains of this construction, which was slightly more than half the size of the present basilica and completed by two belltowers, can be seen today in the archeological area underneath the Cathedral.

Brunelleschi drew his inspiration from double-walled cupola of the Pantheon in Rome. He constructed a wooden and brick model with the help of Donatello and Nanni di Banco (on display in the Museum Opera del Duomo). Brunelleschi won by a nose. His model served as a guide for the craftsmen, but was intentionally incomplete, as to ensure his control over the construction.

Brunelleschi's solutions were ingenious and unprecedented: the distinctive octagonal design of the double-walled dome, resting on a drum and not on the roof itself, allowed for the entire dome to be built without the need for scaffolding from the ground.