Hake Gallery | Duomo Videos

Hake Gallery


Welcome to Hake Gallery. A Family Photo and Video Site

Hake Gallery | Italy 2010 | Basilica Santa Maria del Fiore | Duomo Videos

A circular masonry dome, such as that of Hagia Sophia in Istanbul 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 centimetres (2 ft) thick at the base and 30 centimetres (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 at its base; it has no embedded chains.

A modern understanding of physical laws and the mathematical tools for calculating stresses were centuries into 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.

Ghiberti, appointed coadjutator, was drawing a salary equal to Brunelleschi's and would potentially earn equal credit, while spending most of his time on other projects. When Brunelleschi became ill, or feigned illness, the project was briefly in the hands of Ghiberti. But Ghiberti soon had to admit that the whole project was beyond him. In 1423 Brunelleschi was back in charge and took over sole responsibility.

Work started on the dome in 1420 and was completed in 1436. The cathedral was consecrated by Pope Eugene IV on March 25, 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 wooden supporting frame (The Roman Pantheon, a circular dome, was built in 117–128 A.D. with support structures). It was one of the most impressive projects of the Renaissance. During the consecration service in 1436, Guillaume Dufay's similarly unique motet Nuper rosarum flores was performed. The structure of this motet was strongly influenced by the structure of the dome.

Brunelleschi's ability to crown the dome with a lantern was questioned and he had to undergo another competition. He was declared the winner over his competitors Lorenzo Ghiberti and Antonio Ciaccheri. His design was for an octagonal lantern with eight radiating buttresses and eight high arched windows (now on display in the Museum Opera del Duomo). 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 metres (375 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.