Florence Cathedral (Italian: Duomo di Firenze),
formally the Cathedral of Saint Mary of the Flower (Italian: Cattedrale di Santa Maria del Fiore),
is the cathedral of the Catholic Archdiocese of Florence in Florence, Italy.

Commenced in 1296 in the Gothic style to a design of Arnolfo di Cambio and completed by 1436 with a dome engineered by Filippo Brunelleschi, the basilica's exterior is faced with polychrome marble panels in various shades of green and pink, alternated by white, and features an elaborate 19th-century Gothic Revival western façade by Emilio De Fabris.

The cathedral complex, in Piazza del Duomo, includes the Florence Baptistery and Giotto's Campanile. These three buildings are part of the UNESCO World Heritage Site covering the historic centre of Florence and are a major tourist attraction of Tuscany. The basilica is one of world's largest churches and its dome is still the largest masonry dome ever constructed. The cathedral is the mother church and seat of the Archdiocese of Florence, whose archbishop is Gherardo Gambelli.

History

Santa Maria del Fiore was built on the site of Florence's second cathedral dedicated to Saint Reparata; the first bishop's seat was the Basilica of San Lorenzo, the initial building of which was consecrated as a church in 393 by St. Ambrose of Milan. The ancient structure, founded in the early 5th century and having undergone many repairs, was crumbling with age, according to the 14th-century Nuova Cronica of Giovanni Villani, and was no longer large enough to serve the growing population of the city. Other major Tuscan cities had undertaken ambitious reconstructions of their cathedrals during the Late Medieval period, such as Pisa and particularly Siena where the enormous proposed extensions were never completed.

The city council of Florence approved Arnolfo di Cambio's design for the new church in 1294. Di Cambio was also architect of the church of Santa Croce and the Palazzo Vecchio. He designed three wide naves ending under an octagonal dome, with the middle nave covering the area of Santa Reparata. The first stone was laid on 9 September 1296, by Cardinal Valeriana, the first papal legate ever sent to Florence. The building of this vast project was to last 140 years; Arnolfo's plan for the eastern end, although maintained in concept, was greatly expanded in size.

After Arnolfo died in 1302, building of the cathedral slowed for almost 50 years. When the relics of Saint Zenobius were discovered in 1330 in Santa Reparata, the project gained a new impetus. In 1331, the Arte della Lana, the guild of wool merchants, took over patronage for the construction of the cathedral and in 1334 appointed Giotto to oversee the work. Assisted by Andrea Pisano, Giotto continued di Cambio's design. His major contribution was to design and begin the construction of the campanile. When Giotto died on 8 January 1337, Andrea Pisano continued the building until work was halted due to the Black Death in 1348.

In 1349, action resumed on the cathedral under a series of architects, starting with Francesco Talenti, who finished the campanile and enlarged the overall project to include the apse and the side chapels. In 1359, Talenti was succeeded by Giovanni di Lapo Ghini (1360–1369) who divided the centre nave into four square bays. Other architects were Alberto Arnoldi, Giovanni d'Ambrogio, Neri di Fioravanti and Andrea Orcagna. By 1375, the old church of Santa Reparata was pulled down. The nave was finished by 1380, and only the dome remained incomplete until 1436.

On 19 August 1418, the Arte della Lana announced an architectural design competition for erecting Neri's dome. The two main competitors were two master goldsmiths, Lorenzo Ghiberti and Filippo Brunelleschi, the latter of whom was supported by Cosimo de' Medici. Ghiberti had been the winner of a competition for a pair of bronze doors for the Baptistery in 1401 and lifelong competition between the two seem to remain. Brunelleschi won and received the commission.

Ghiberti, appointed coadjutor, drew a salary equal to Brunelleschi's and, though neither was awarded the announced prize of 200 florins, was promised equal credit, although he spent most of his time on other projects. When Brunelleschi became ill, or feigned illness, the project was briefly in the hands of Ghiberti, but soon he supposedly had to admit that the whole project was beyond him. In 1423, Brunelleschi was back in charge and took over sole responsibility.

Erection of the dome had begun in 1420 and was finished in 1436. The cathedral was consecrated by Pope Eugene IV on 25 March 1436, the first day of the year according to the Florentine calendar. It was the first 'octagonal dome in history to be built without a temporary wooden supporting frame. During the consecration in 1436, Guillaume Dufay's motet Nuper rosarum flores was performed.

The decoration of the exterior of the cathedral, begun in the 14th century, was left unfinished after the initial works done by Arnolfo di Cambio, which led Lorenzo de' Medici to initiate a design competition for the façade between 1490 and 1491. The competition went ultimately nowhere, and the façade wasn't installed until the 19th century, in 1887, with the fabrication of Emilio De Fabris' polychrome marble design. The floor of the church had been relaid in marble tiles in the 16th century.

The exterior walls are faced in alternate vertical and horizontal bands of polychrome marble from Carrara (white), Prato (green), Siena (red), Lavenza and a few other places. De Fabris had to copy the initially Romanesque cladding style peculiar to Tuscan church architecture such as the earlier baptistery (Battistero di San Giovanni), and Giotto's bell tower. There are two major side doors near the crossing: the Porta dei Canonici on the south side and the Porta di Mandorla to the north. The mandorla with the Madonna of the Girdle surrounded by angels was sculpted by Nanni di Banco. Nanni who worked with his father and others on the door, died way too early before the portal was completed. Nanni and the befriended young Donatello provided two youthful prophet figures for the top of the pinnacles flanking the portal which are now in the Museo dell'Opera del Duomo. The six side windows, notable for their delicate tracery and ornaments, are separated by pilasters. Only the four windows closest to the transept admit light; the other two are merely ornamental. The clerestory windows are round, a common Italian Gothic feature.

Exterior

The cathedral of Florence is built as a basilica, having a wide central nave of four square bays, with an aisle on either side. The chancel and transepts are of identical polygonal plan, separated by two smaller polygonal chapels. The whole plan forms a Latin cross. The nave and aisles are separated by wide pointed Gothic arches resting on composite piers.

Its arrangement of trilobate -three lobe- apses was intended to evoke the form of a flower, as a homage to Fiorenza, the "city of flowers".

The dimensions of the building are enormous: building area 8,300 m2 (89,340 sq ft), length 153 m (502 ft), width 38 m (125 ft), width at the crossing 90 m (300 ft). The height of the arches in the aisles is 23 m (75 ft). The height of the dome is 114.5 m (375.7 ft). It has the fifth tallest dome in the world.

The Overseers of the Office of Works of Florence Cathedral, the Arte della Lana, had plans to commission a series of twelve large Old Testament sculptures for the buttresses of the cathedral. Donatello, then in his early twenties, was commissioned to carve a statue of David in 1408, to top one of the buttresses, though it was never placed there. Nanni di Banco was commissioned to carve a marble statue of Isaiah, at the same scale, in the same year. One of the statues was lifted into place in 1409, but was found to be too small to be easily visible from the ground and was taken down; both statues then languished in the workshop of the opera for several years. In 1409–1411 Donatello made a statue of a sitting Saint John the Evangelist which until 1588 was in a niche of the old cathedral façade. Between 1415 and 1426, Donatello created five statues for the campanile of Santa Maria del Fiore. These are the Beardless and the Bearded Prophet (both from 1415); the Sacrifice of Isaac (1421); Habbakuk (1423–25); and Jeremiah (1423–26); which follow the classical models for orators and are characterized by strong portrait details. A figure of Hercules, in terracotta, was commissioned from the Florentine sculptor Agostino di Duccio in 1463 and was made perhaps under Donatello's direction. A statue of David by Michelangelo was completed 1501–1504 although it could not be placed on the buttress because of its six-ton weight. In 2010 a fiberglass replica of "David" was placed for one day on a roof-top buttress for a chapel's dome.

After a hundred years of construction and by the beginning of the 15th century, the structure was still missing its dome. The basic features of the dome had been designed by Arnolfo di Cambio in 1296. His brick model, 4.6 m (15.1 ft) high, 9.2 m (30.2 ft) long, was standing in a side aisle of the unfinished building, and had long been sacrosanct. It called for an octagonal dome higher and wider than any that had ever been built, with no external buttresses to keep it from spreading and falling under its own weight. 

The commitment to reject traditional Gothic buttresses had been made when Neri di Fioravanti's model was chosen over a competing one by Giovanni di Lapo Ghini. That architectural choice, in 1367, was one of the first events of the Italian Renaissance, marking a break with the Medieval Gothic style and a return to the classic Mediterranean dome. Italian architects regarded Gothic flying buttresses as ugly makeshifts. Furthermore, the use of buttresses was forbidden in Florence, as the style was favored by central Italy's traditional enemies to the north. Neri's model depicted a massive inner dome, open at the top to admit light, like Rome's Pantheon, partly supported by the inner dome, but enclosed in a thinner outer shell, to keep out the weather. It was to stand on an unbuttressed octagonal drum. Neri's dome would need an internal defense against spreading (hoop stress), but none had yet been designed.

The building of such a masonry dome posed many technical problems. Brunelleschi looked to the great dome of the Pantheon in Rome for solutions. The dome of the Pantheon is a single shell of concrete, the formula for which had long since been forgotten. The Pantheon had employed structural centring to support the concrete dome while it cured. This could not be the solution in the case of a dome this size and would put the church out of use. For the height and breadth of the dome designed by Neri, starting 52 m (171 ft) above the floor and spanning 44 m (144 ft), there was not enough timber in Tuscany to build the scaffolding and forms. Brunelleschi chose to follow such design and employed a double shell (a type of dome construction that was developed under the Seljuk Empire) made of sandstone and marble. Brunelleschi would have to build the dome out of brick, due to its light weight compared to stone and being easier to form, and with nothing under it during construction. To illustrate his proposed structural plan, he constructed a wooden and brick model with the help of Donatello and Nanni di Banco, a model which is still displayed in the Museo dell'Opera del Duomo. The model served as a guide for the craftsmen, but was intentionally incomplete, so as to ensure Brunelleschi's control over the construction.

Brunelleschi's solutions were ingenious. The spreading problem was solved by a set of four internal horizontal stone and iron chains, serving as barrel hoops, embedded within the inner dome: one at the top, one at the bottom, with the remaining two evenly spaced between them. A fifth chain, made of wood, was placed between the first and second of the stone chains. Since the dome was octagonal rather than round, a simple chain, squeezing the dome like a barrel hoop, would have put all its pressure on the eight corners of the dome. The chains needed to be rigid octagons, stiff enough to hold their shape, so as not to deform the dome as they held it together.

Each of Brunelleschi's stone chains was built like an octagonal railroad track with parallel rails and cross ties, all made of sandstone beams 43 cm (17 in) in diameter and no more than 2.3 m (7.5 ft) long. The rails were connected end-to-end with lead-glazed iron splices. The cross ties and rails were notched together and then covered with the bricks and mortar of the inner dome. The cross ties of the bottom chain can be seen protruding from the drum at the base of the dome. The others are hidden. Each stone chain was supposed to be reinforced with a standard iron chain made of interlocking links, but a magnetic survey conducted in the 1970s failed to detect any evidence of iron chains, which if they exist are deeply embedded in the thick masonry walls. Brunelleschi also included vertical "ribs" set on the corners of the octagon, curving towards the center point. The ribs, 4 m (13 ft) deep, are supported by 16 concealed ribs radiating from center. The ribs had slits to take beams that supported platforms, thus allowing the work to progress upward without the need for scaffolding.

A circular masonry dome can be built without supports, called centering, because each course of bricks is a horizontal arch that resists compression. In Florence, the octagonal inner dome was thick enough for an imaginary circle to be embedded in it at each level, a feature that would hold the dome up eventually, but could not hold the bricks in place while the mortar was still wet. Brunelleschi used a herringbone brick pattern to transfer the weight of the freshly laid bricks to the nearest vertical ribs of the non-circular dome.

The outer dome was not thick enough to contain embedded horizontal circles, being only 60 cm (2 ft) thick at the base and 30 cm (1 ft) thick at the top. To create such circles, Brunelleschi thickened the outer dome at the inside of its corners at nine different elevations, creating nine masonry rings, which can be observed today from the space between the two domes. To counteract hoop stress, the outer dome relies entirely on its attachment to the inner dome and has no embedded chains.[38]

A modern understanding of physical laws and the mathematical tools for calculating stresses were centuries in the future. Brunelleschi, like all cathedral builders, had to rely on intuition and whatever he could learn from the large scale models he built. To lift 37,000 tons of material, including over 4 million bricks, he invented hoisting machines and lewissons for hoisting large stones. These specially designed machines and his structural innovations were Brunelleschi's chief contribution to architecture. Although he was executing an aesthetic plan made half a century earlier, it is his name, rather than Neri's, that is commonly associated with the dome.

Brunelleschi's ability to crown the dome with a lantern was questioned and he had to undergo another competition, even though there had been evidence that Brunelleschi had been working on a design for a lantern for the upper part of the dome. The evidence is shown in the curvature, which was made steeper than the original model.[39] He was declared the winner over his competitors Lorenzo Ghiberti and Antonio Ciaccheri. His design (now on display in the Museum Opera del Duomo) was for an octagonal lantern with eight radiating buttresses and eight high arched windows. Construction of the lantern was begun a few months before his death in 1446. Then, for 15 years, little progress was possible, due to alterations by several architects. The lantern was finally completed by Brunelleschi's friend Michelozzo in 1461. The conical roof was crowned with a gilt copper ball and cross, containing holy relics, by Verrocchio in 1469. This brings the total height of the dome and lantern to 114.5 m (376 ft). This copper ball was struck by lightning on 17 July 1600 and fell down. It was replaced by an even larger one two years later.

The commission for this gilt copper ball [atop the lantern] went to the sculptor Andrea del Verrocchio, in whose workshop there was at this time a young apprentice named Leonardo da Vinci. Fascinated by Filippo's [Brunelleschi's] machines, which Verrocchio used to hoist the ball, Leonardo made a series of sketches of them and, as a result, is often given credit for their invention.

Leonardo might have also participated in the design of the bronze ball, as stated in the G manuscript of Paris "Remember the way we soldered the ball of Santa Maria del Fiore".

The decorations of the drum gallery by Baccio d'Agnolo were never finished after being disapproved by no one less than Michelangelo.

A huge statue of Brunelleschi now sits outside the Palazzo dei Canonici in the Piazza del Duomo, looking thoughtfully up towards his greatest achievement, the dome that would forever dominate the panorama of Florence. It is still the largest masonry dome in the world.

The building of the cathedral had started in 1296 with the design of Arnolfo di Cambio and was completed in 1469 with the placing of Verrochio's copper ball atop the lantern. But the façade was still unfinished and would remain so until the 19th century.

The original façade, designed by Arnolfo di Cambio and usually attributed to Giotto, was actually begun twenty years after Giotto's death.[citation needed] A mid-15th-century pen-and-ink drawing of this so-called Giotto's façade is visible in the Codex Rustici, and in the drawing of Bernardino Poccetti in 1587, both on display in the Museum of the Opera del Duomo. This façade was the collective work of several artists, among them Andrea Orcagna and Taddeo Gaddi. This original façade was completed in only its lower portion and then left unfinished. It was dismantled in 1587–1588 by the Medici court architect Bernardo Buontalenti, ordered by Grand Duke Francesco I de' Medici, as it appeared totally outmoded in Renaissance times. Some of the original sculptures are on display in the Museum Opera del Duomo, behind the cathedral. Others are now in the Berlin Museum and in the Louvre.

The competition for a new façade turned into a huge corruption scandal. The wooden model for the façade of Buontalenti is on display in the Museum Opera del Duomo. A few new designs had been proposed in later years, but the models (of Giovanni Antonio Dosio, Giovanni de' Medici with Alessandro Pieroni and Giambologna) were not accepted. The façade was then left bare until the 19th century.

In 1864, a competition held to design a new façade was won by Emilio De Fabris (1808–1883) in 1871. Work began in 1876 and was completed in 1887. This neo-gothic façade in white, green and red marble forms a harmonious entity with the cathedral, Giotto's bell tower and the Baptistery.

On top of the façade is a series of niches with the twelve Apostles with, in the middle, the Madonna with Child. Between the rose window and the tympanum, there is a gallery with busts of great Florentine artists.

Crypt

The cathedral underwent difficult excavations between 1965 and 1974. The archaeological history of this huge area was reconstructed through the work of Franklin Toker: remains of Roman houses, an early Christian pavement, ruins of the former cathedral of Santa Reparata and successive enlargements of this church. Close to the entrance, in the part of the crypt open to the public, is the tomb of Brunelleschi. While its location is prominent, the actual tomb is simple and humble. That the architect was permitted such a prestigious burial place is proof of the high esteem he was held in by the Florentines.

• Zenobius of Florence
• Conrad II of Italy
• Giovanni Benelli
• Filippo Brunelleschi
• Giotto di Bondone
• Pope Nicholas II
• Pope Stephen IX
• John Hawkwood