It was considered the greatest architectural puzzle of its age. Many said it couldn't be done. Nothing even close to its size had been built since antiquity. It would have a diameter of 143 feet and would exceed the span of the Pantheon in Rome which had reigned as the world's largest dome for over 1000 years. The dome for Santa Maria del Fiore, the new cathedral in Florence, would not only be the widest dome ever built, it would also be the highest.
But who could build it? And how?
On August 19, 1418 the Opera del Duomo in Florence announced a competition:
"Whoever desires to make any model or design for the vaulting of the main Dome of the Cathedral under construction by the Opera del Duomo -- for armature, scaffold or other thing, or any lifting device pertaining to the construction and perfection of said cupola or vault -- shall do so before the end of the month of September. If the model be used he shall be entitled to a payment of 200 gold Florins."
Ross King's 2000 national bestseller, Brunelleschi's Dome: How a Renaissance Genius Reinvented Architecture tells the tale of how a 41-year-old goldsmith and clockmaker, Filippo Brunelleschi, won the competition and devoted the rest of his life to solving the monumental puzzles of the dome's construction.
A model of the vaulted dome, considered sacrosanct by the Opera, had been in place since 1367. Neri di Fiorvanti's bold design rejected the use of external supports such as flying buttresses, which were considered ugly and awkward by Italian architects. Instead, he designed the double-skinned dome to be supported by a series of internal circumferential rings that would make the dome seem to rise skyward without any visible means of support.
The problems faced by Brunelleschi were practical but daunting: how to support the weight of the massive dome without external support, how to safely build it without scaffolding and how to hoist an estimated 70 million tons of building materials several hundred feet above the ground and put them into position with pinpoint accuracy. Brunelleschi's winning proposal for building the dome not only did away with any external support, it also did away with the wooden centering used for building even the smallest of arches. His daring ideas combined with his penchant for secrecy led many to consider him a madman.
Author Ross takes Brunelleschi's enormous challenges and sets them against a background of bitter rivalry, political intrigue, Black Plague, imprisonment and war, weaving a fascinating tale of against-all-odds achievement. You begin to understand the scope of ingenuity, tenacity and determination that Brunelleschi possessed to have accomplished the seemingly impossible.
Keep in mind that this was the 15th century -- you couldn't make a phone call or two and order the required building equipment. Before construction could begin, Brunelleschi had to design and build a hoist to lift the huge weight of the building materials hundreds of feet off the cathedral floor. This complicated hoist, just one of many machines Brunelleschi invented for constructing the dome, went on to become one of the most celebrated machines of the Renaissance.
And consider the working conditions! The masons worked in a small space between the two skins of the dome, reached by climbing stairs the equivalent of 40 stories high to work each morning. They carried their tools and lunch with them, forbidden as they were from using the hoist. There was no system of scaffolding to break a fall -- the masons moved around the outer layer of the cupola on narrow platforms made from willow branches supported by wooden rods inserted into the masonry, the only thing between them and a drop of several hundred feet to certain death. And yet, despite these conditions, only one worker died in the 16 years it took to build the dome.
After 140 years of construction, Santa Maria del Fiore was finally consecrated in 1436. A 1000-foot-long raised wooden platform, bedecked with flowers, was erected to carry Pope Eugenius IV safely above the crowds for the ceremony.
The dome, however, was not complete. The exterior surface had yet to be tiled and the facings of colored marble would take another generation to complete. The lantern at the top of the dome had to be designed and built. Yet another competition was announced, and again Brunelleschi's design won.
The first stone of the lantern was consecrated in March 1446. Brunelleschi died a month later after a short illness. He was 69 years old and had worked on the cathedral site for more than a quarter of a century. Ross ends his tale by saying of Brunelleschi:
"In his unquestionable brilliance the writers of the Renaissance found their proof that modern man was as great as -- and could in fact surpass -- the ancients from whom they took their inspiration."