The dome, which dominates the Florence skyline, posed many technical problems with a number of designs being implemented and failing. It was built in the end from a design by Brunelleschi, and consisted of an inner and outer dome. Both domes are supported using 24 stone ribs located by metal cramps to minimize outward thrust. The lower levels were constructed using stone with the higher levels built in brick to reduce weight.
The Duomo Cathedral or Santa Santa Maria del Fiore, is located in the Piazza del Duomo and is the mother church of the Roman Catholic Archdiocese of Florence. Built on the site of a much older cathedral, the Duomo was built from an original design by Arnolfo di Cambio, who also designed the Santa Croce and the Palazzo Vecchio. Construction commenced in 1296 and would continue for the next 170 years. Giotto was appointed to oversee construction in 1331 who was followed after his death by his assistant Andrea Pisano, but work came to a halt in 1348 due to the Black Death sweeping Europe, but a year later, work was resumed and continued under the watchful eye of a number of further architects until the work was deemed finished.
The facade, although often attributed to Giotto, was actually started 20 years after his death. And has been remodeled a number of times. In 1864 a competition to design a new facade was held. In The winner, Emilio de Fabris, started work in 1871 but the work was not completed until 1887, 4 years after his death. It is this facade in the neo-gothic style with white, green, and red marble that can be seen today.
The huge Gothic interior is relatively bare as many of its treasures have disappeared over time, or been moved to other locations such as the Museum Opera del Duomo. Sitting above the main entrance door is a very large clock, on its face are the portraits of four Prophets by the artist Paolo Uccello. The clock has a single hand and works on a 24 hour system ending at sunset, this is known as “hora italica” or “Italian time”. This system was used in Italy until the 18th century, and this is one of the few remaining clocks of its kind in working order. Many of the decorations such as the coloured marble pavement date from the 16th century and are due to the patronage of the Grand Dukes. The crucifix at the high alter, is by Benedetto da Maiano, the enclosure for the choir is by Bartolommeo Bandinelli. Located at the back of the centre apse is an alter by Ghiberti and contains an urn which contains the relics of the first bishop of Florence, Saint Zanobius.
The Duomo boasts 44 superb stained glass windows dating from the 14th and 15th centuries. Saints from the Old and New Testaments are depicted in the aisles and transept, plus there are circular windows located above the entrance and in the drum of the dome, which depict Christ and Mary. These windows are the work of a number of the greatest artists at the time working in Florence, including Andrea del Castagno, Donatello, Lorenzo Ghiberti, and Paolo Uccello.