Possible 9-foot model of Brunelleschi’s dome found
It was found in a layer two-and-a-quarter feet below surface level which contains copious metal and marble fragments from the period when the space was used as a construction workshop during the late 14th and 15th centuries, the same time when Brunelleschi was working on his dome. Herringbone brickwork had been used before in Persian domes, but Brunelleschi’s was the first in Europe, which means this model may be the first brick herringbone dome built on the continent.
In 1418 the wool guild sponsored a contest to solve the thorny problem. Brunelleschi studied the dome of the Pantheon in Rome — still today the largest unreinforced concrete dome in the world — but he couldn’t use the Pantheon’s techniques for the Duomo dome. The Roman recipe for concrete was lost, for one thing, and for another, it had required massive wooden forms to keep the dome standing while the concrete dried. There literally wasn’t enough timber in Tuscany to scaffold and frame even a masonry dome 144 feet in diameter. Also the outer walls of the cathedral had already been built, and there was no way they could withstand the compression forces of a massive, heavy dome. Besides, there was still the stricture that the interior of the church had to be open to the public during construction.
Even today there are many questions about how he accomplished this extraordinary feat of architecture. Brunelleschi kept his overall plan close to his chest, releasing snippets on a need-to-know basis so he couldn’t be easily replaced. The discovery of a brick and mortar model (as opposed to the small mock-up style model which is on display at the Museum of the Works of the Cathedral) could add to our understanding of Brunelleschi’s methods.
In the 1900s the theater was gutted and used as a garage until it was purchased by its former owners, the Works of the Duomo, in 1998. For the next decade or so, the organization used it for storage and as a restoration laboratory. In 2009, construction began to transform the space into an adjunct space for the museum. The new addition is scheduled to open in 2015. The newly discovered domelet will be fully excavated, restored as much as feasible and put on display in the new museum.