On an August morning 590 years ago a group of workmen climbed about 250 steps and walked out onto a fourteen foot wide platform.Above them was sky, and looking 170 feet straight down they saw the floor of a cathedral.Across they saw a large octagonal hole in the cathedral’s roof measuring about 140 feet across (almost the width of a football field).On that day they would begin construction of a dome over this opening.“Are you sure this will work?” was surely on many of the workmen’s minds that morning, and on the minds of thousands of people on the streets far below…nothing like this had ever been done.
History records a tremendous number of feats undertaken by societies and individuals that moved mankind beyond previously held boundaries.Many of these feats have involved remarkable courage, especially heroic efforts by men and women to unshackle themselves from the vices of tyranny.Other feats have involved individual genius where established norms and practices are uprooted by daring artistic and technological achievements and inventions.
The purpose of this article is to make the case that no single feat in recorded history has involved a greater combination of courage and genius than the construction of this dome over Santa Maria Del Fiore in Florence, Italy.I acknowledge that the courage required for this construction does not compare to the courage demonstrated by men and women who have fought and died in wars, revolutions, and in defense of their convictions and faith.Nor do I contend that the genius needed to build this dome compares to inventions that have permanently transformed our civilization.I simply believe that no feat more effectively combined both courage and genius than the effort that went into the construction of this dome.
It is almost humorous how the Florentines found themselves in the situation where the dome needed to be built in the first place.It is a story whose roots went back almost 130 years before this August morning in 1420.As a proud and prosperous republic in the 13th century, the leaders of Florence determined that they should construct the most magnificent cathedral known to man.This was quite a mission.In the previous 200 years some stunningly large and beautiful cathedrals had been completed in Northern Europe.
This was a time when Florence was the financial capital of the world, the Wall Street of its time.Its currency, the florin, was the international monetary standard and their banks were dominant throughout Europe and parts of Asia.Internally the city was home to many prosperous commercial enterprises, each controlled by associations of their respective tradesmen and master craftsmen called guilds.The role of these guilds was to oversee the quality and practices of their industry, but they were each also given specific civic, religious, and charitable responsibilities.The responsibility for overseeing the design and construction of Florence’s preeminent cathedral was given to the Wool Merchants Guild, the city’s wealthiest and most powerful.Florence’s wool industry imported English wool and processed it with exotic dyes from Tuscany and Asia, making the most sought-after cloth in Europe.The Wool Merchants Guild assigned a Council to administer the cathedral project who then appointed knowledgeable architects and craftsmen to perform the work.
In the previous centuries architects had advanced their structural mastery to allow cathedrals to soar in height.The Cathedral of Notre Dame in Paris was built 102 feet tall and was soon eclipsed by a cathedral in Chartres that reached 120 feet.As more Cathedrals were built throughout Europe architects continued to test the structural limits until, as you might expect, a Cathedral in Beauvais, France collapsed.It had attempted to reach 157 feet, and though some of this church remains today it appears as an unfinished monument to reckless architectural ambition.
Another ambitious church was the Hagia Sophia in Istanbul, Turkey.This amazing structure was begun in 532 A.D. and included a beautiful dome, 102 feet in diameter, with forty windows around its base.The light from these windows gave visitors the impression that the dome was suspended from heaven, an impression proven wrong when it collapsed soon after being built.The dome was rebuilt and then collapsed again in the 10th Century.It was modified and rebuilt once more and today continues to thrill visitors, but it also serves as an example of overly bold architectural ventures.
Despite the time and distance between these structural failures and 14th Century Florence, the Wool Guild planners were well aware of these failures.However, the traits of prudence and pragmatism were not highly regarded in Florence at this time, and in the year 1296 A.D. construction of their grandiose cathedral moved forward.
THE WORK BEGINS
The Wool Guild Council chose a site in the center of the city and began building foundations for the new cathedral.The plans featured a long nave, aisles, and three transepts intersecting to create a large crossing, over which a dome would be placed.A large model of the finished cathedral was placed next to the construction site for the citizens to marvel at and the workmen to use as a guide.At this time the architects had no idea how this dome would actually be constructed; they were led by a faith that God would provide an answer when the time to build it came.Over the next seven decades the walls of the nave were built and vaulted.Work was about to begin on the part of the structure that would support the dome.The aforementioned model intended to guide the design of this area had already collapsed from its own weight.Undeterred by this inauspicious fact, the Council decided to modify their plans.They determined that this part of the cathedral should be even larger, and the height and span of the dome should be even greater.
In 1367 another model of the cathedral was commissioned and placed inside the finished portion of the cathedral.The architect for the modified design was named Neri di Fioravanti, and he not only showed the dome to be much larger, but to include no flying buttresses.These buttresses were a necessary feature of the cathedrals already built in northern Europe.They transferred the lateral forces from these tall structures outward, and down to the ground.But as previously mentioned, even flying buttresses were not enough to prevent the collapse of the cathedral in Beauvais, France in 1284.The new parameters for the dome Neri designed required vaulting that far-exceeded what had been attempted at the collapsed churches in Istanbul and Beauvais, and it would begin much higher above the ground.
Nothing exemplifies the incredible spirit and faith of the Florentines at this time than this fact: between 1348 and 1400, during which much of the planning and construction of the cathedral took place, there were six separate outbreaks of the Black Plague.In1348 the plague claimed over half of Florence’s population, and subsequent outbreaks continued the devastation.The 1400 manifestation took 20% of the remaining population of the city.If this wasn’t enough to squelch the ambitious plans of the city, they were also frequently besieged by invading armies during this period.The fact that the city moved on so boldly during these crises speaks to the amazing confidence and motivation they had.
Over the next several decades the model of the new dome design became a revered item among the builders and the citizens of Florence.The model was large; thirty feet long, fifteen feet high and made from bricks and mortar.Annually the persons responsible for planning and building the cathedral were brought to the model, forced to place their right hand on a bible, and to swear to follow its intent.Sadly this model was demolished a century or so after the cathedral’s completion.Presumably it did not collapse from its own weight as its predecessor had.
The dome Neri presented in 1367 did not bother to include structural design information showing how the dome could be built, but it did call out for the use of an inner and outer dome.This was a practice that had been used in middle-eastern architecture where the inside dome served primarily to support the loads and the outside dome served to protect it from the elements.He also envisioned the use of chains encircling the dome to take the place of the flying buttresses, but said nothing about what these chains would be made from or how they could be built.