In the 15th century, Florence, Italy was becoming a center of wealth and power. And what do the wealthy and powerful often like to do? They like to build something to show it off. What better way for 15th-century florentines to strut their stuff than to build a gigantic church having the biggest dome in the world?
The church would become Santa Maria del Fiore, better-known by visitors today as “The Duomo.” A church already existed on the site, but it wasn’t grand enough for city leaders. They wanted to build a church that made a statement.
The city council planned to revamp and drastically enlarge the existing church. The new church would be larger, grander, and topped with a beautiful dome – at the time, the biggest dome in the world.
But It Wouldn’t Be Easy
The city hired architects and designers for the job. They created multiple designs for the massive structure, but each design had a problem: no one believed that the dome would be structurally strong enough to not cave in on itself.
The designers ran into other serious problems, too. They realized that to build a dome that size, even if the design was structurally sound, the project would require a massive amount of scaffolding. There wasn’t enough wood in all of Tuscany to build the scaffolding required for the job.
Maybe creating this huge church with its impossible-to-build dome wasn’t such a great idea.
Before giving up on the project, the city council decided to sponsor a contest. Maybe some smart guy could figure out how to do it.
These Two Guys Again?
If you’ve been following along, you’ll recognize the names associated with two of the entries – Lorenzo Ghiberti and Filippo Brunelleschi.
That’s right – the same two guys who squared off in the competition to win the job of designing new doors for the Baptistery of Saint John. The job ultimately went to Lorenzo Ghiberti.
The city council’s hopes were high, but after every dome design entry had been evaluated, no one had proposed an acceptable design.
Filippo Brunelleschi said he had a design, but he refused to tell the judges all the details unless he was awarded the prize. (I believe that’s called chutzpah, eh?) Apparently, after the baptistery door contest, he didn’t have a warm, fuzzy feeling for judging committees.
Well, guess what? Brunelleschi convinced the judges that he knew his stuff, and that he had a way to do it. He won the job.
Brunelleschi’s Design
There were quite a few parts to Brunelleschi’s design. One key idea is that there would be ribs inside the dome, like barrel staves on a barrel, except on the inside. These would act as sort of a scaffolding as the dome was being built.
Brunelleschi’s design provided for two domes – a light one on the inside, underneath a big, sturdy one on the outside. They’d build sections of the lighter dome first. Those sections would support workers when they built corresponding sections of the exterior dome.
A third idea concerned brick laying. Bricks would be laid in an interleaved herringbone pattern, allowing workers to lay bricks without having them slip out of place before the mortar dried.
Perhaps the most interesting problem to overcome was how to ensure that the dome would be properly centered. Without having scaffolding built up underneath, the dome would have to be built strictly from the outside in.
Not only that, but as workers built up the layers, the angle of bricks would change as they went up. They’d be almost flat at the bottom, but slanted quite a bit near the top. How would Brunelleschi know how much to slant them at any given level?
If he wasn’t careful, he could build the dome halfway up before finding out it was going to be lop-sided.
He Didn’t Save His Work
Brunelleschi solved those problems using some clever geometry, but luckily for us, he didn’t leave anything laying around that explained how he did it. People have their theories, but let’s leave those to the mathematicians.
Instead, let’s move on to the machines Brunelleschi invented to get the job done, because they’re really neat.
To be continued…
