Animated Journeys : Florence Cathedral - The story of the largest masonry dome in world

"Create with the heart, Build with the mind"

Florence cathedral or Duomo, known locally as Santa Maria del Fiori had its humble beginnings in the year 1292. The construction began in the gothic style with pointed arches and vaulted ceilings. The cathedral had been started in order to showcase the status of Florence as one of Europe's economic and cultural capitals. It was later decided that the cathedral would be embellished with a dome, the size of which would be more than any other ever built.

The cathedral had been expanded from its original design and was functional for about 125 years without any cover over the place, where the high altar should have been. As a result the rainy water would enter the inside of the cathedral season after season.

Ultimately in 1418 the town fathers of Florence finally decided to address this issue. The reason for this delay was the fact that nobody had an idea how to build a dome which would have to begin upwards on an octagonal frame already in position 180 feet high. Importantly the dome would have to be 150 feet across. One thing was clear in the minds of town fathers that design would have nothing to do with the typical Gothic style consisting of flying buttresses and pointed arches, the one followed by Milan, Florence's archenemy. As luck would have it, these were the only solutions available at the time. The question of availability of timber for scaffolding and the question whether the dome of masonry would not collapse inwards by thousands of tons of weight was weighing heavily on everyone's mind.

In 1418 the fathers of Florence decided to hold a contest to build the dome with a prize of 200 gold florins. The contest resulted in production of many ideas, some funny and some interesting but foolish, to solve the problem.

An interesting and innovative solution was offered by a goldsmith and not an architect, that he would build two domes, one nestled inside the other, without the need for elaborate and extensive scaffolding. As the goldsmith Fillipo Brunelleschi was secretive lest his idea be stolen, he would not divulge the details of his construction plans. After much discussions and having experienced his design of a brass door 15 years ago, the fathers of Florence knew his ingenuity and hence the project was ultimately given to him.

His dome would consist of two concentric shells, an inner one visible from within the cathedral nestled inside a wider, taller dome. To counteract the outward bulging pressure created by the structure's weight he would bind the walls with tension rings of stone, iron and wood like hoops on a barrel

The project took 16 years to complete. Brunelleschi was lucky enough to see the completed dome in his life time with utmost satisfaction. His double shell design yielded a structure that was far lighter and loftier than a solid dome. He wove regular courses of HERRINGBONE pattern brickwork, little known before his time into the texture of cupola, giving the entire structure additional solidity.

He was also the one to innovate the design of pulleys and levers and was the first to introduce reverse gear, which would lift up and down the heavy construction material with the help of two bullocks, moving all day in one circular motion.

On march 25, 1436 Pope Eugenius IV consecrated the finished cathedral to tolling of bells and cheering by Florintines. A decade later another group laid the decorative marble lantern on top of the dome as a crown.

Brunelleschi was a very secretive person and left no maps, drawing or any notes of his construction plans or progress. As a result the exact detail of how such a large dome was built, still remains shrouded in mystery. Till date, even after 600 years of its existence, this dome remains the largest dome of masonry ever built.

The climb to the top is by using the steps of the staircase between the two layers of the dome. This staircase was originally built for workers to go up and down to the level of construction. The climb is only one metre wide and is quite claustrophobic and there are 464 steps to the top and base of lantern.