The usual way to build an arch or dome was to support it with scaffolding called "centring". This was not as easy in this case because there was an opening in the cathedral that was 42m in width. This created a problem because the Florentines wanted a very tall and impressive dome. The dimensions of the octagonal dome were a significant problem.
Some people suggested that they should build piers from the ground that had arches on them so that they could prop the weight of the dome up. Some
people even suggested that the dome should be made out of pumice-stone because it weighs less. Despite the many problems that they were running into, the people of Florence had faith that God would one day send a man to them who could find a way to build this dome.
Brunelleschi was a talented man. He was fascinated by the construction of the Pantheon and how it stayed up. This was helpful in the process of finding a way to build the dome in Florence. After a while of pondering and seeking answers, Brunelleschi decided that he would build the dome without scaffolding. This would be done in such a way that it would end up supporting itself. People soon realized just how risky this idea was; however, they also realized what a brilliant idea Brunelleschi had come up with.
Brunelleschi’s dome would be made of two concentric shells, and then and inner dome along with an external dome. This dome did not have a spire because of the hole in the roof. Even after the dome was complete, people questioned it. They questioned things such as the maintenance need for the curvature of the dome. In the end, Brunelleschi built an amazing work of art.