15th Century Art, Brunelleschi

 

In the early 15th century, there was a competition to design the bronze doors for the Baptistery of San Giovanni in Florence. The two main competitors were Filippo Brunelleschi and Lorenzo Ghiberti. Their panels both depicted the biblical story of Abraham preparing to sacrifice his son, Isaac. The panel by Brunelleschi has a more rigid composition with figures that appear less three-dimensional. It emphasizes the narrative of the scene, making it easy to follow, but it does not incorporate the depth and perspective that would later become central to Renaissance art.

Ghiberti’s panel is more intricate, with greater attention to perspective and the arrangement of figures in space. His use of foreshortening, a technique that makes objects appear to recede into the background, gives his panel a more lifelike quality. Some of the details in his work, however, make the scene more difficult to interpret at first glance.

Art historians generally agree that Ghiberti won the competition. However, some sources suggest that the judges originally declared a tie and asked both artists to collaborate. According to some accounts, Brunelleschi refused to work together and withdrew, leaving Ghiberti to complete the commission.

Brunelleschi later shifted his focus to architecture. He played a major role in the completion of Santa Maria del Fiore, commonly known as Florence Cathedral. The cathedral had been under construction since the late 13th century, with several architects contributing to its design. The campanile (bell tower) was designed by Giotto di Bondone in the 14th century.

 

One of the main challenges in finishing the cathedral was constructing the dome. The space left for the dome was large, and there was no clear solution at the time for how to build it without the use of traditional wooden centering, which would have been difficult given the scale. Brunelleschi, working between 1420 and 1436, developed an innovative method that allowed the dome to be built using a herringbone brick pattern and a system of interlocking ribs for support. His approach allowed the dome to be constructed without external scaffolding, making it one of the most significant engineering achievements of the period.

During the Renaissance, new wealth led to increased interest in construction projects, but many patrons wanted to see results within their lifetimes. Instead of commissioning entire cathedrals, they often funded smaller chapels or decorative elements that could be completed more quickly. An example of this is Giotto’s work in the Scrovegni Chapel.

The Medici family, however, took a different approach. They supported the completion of Florence Cathedral and ensured that a dome would be built. The overall design of the cathedral follows a Romanesque layout, but the structural details vary. The vaulting inside is Gothic, featuring ribbed groin vaults. The dome itself belongs to the Renaissance period. The building’s exterior was completed later, and the facade was redone in the 19th century. The design of the facade has elements that resemble Byzantine architecture.

The front of the cathedral has decorative patterns that resemble the exterior of the Baptistery of Pisa. The design creates a layered effect, possibly an intentional reference to architectural styles from the 13th century and earlier Byzantine periods. Inside, the pointed arches and rib vaults define the space. The cathedral has two side aisles with pointed arches, which are also used at the far end of the building. The structural details and materials reflect different architectural influences, with the interior being primarily Gothic.

The area where the transept meets the nave creates a large open space at the crossing of Florence Cathedral. Brunelleschi was tasked with solving the structural challenge of completing the dome. The cathedral follows a Latin cross plan, and the original design intended for the dome to be a perfect circle, similar to the Pantheon in Rome. Instead, Brunelleschi created an octagonal design, dividing it into segments to improve stability. The shape made the structure stronger and allowed it to be built without traditional wooden centering, which was difficult for a dome of this scale. 

Brunelleschi had traveled to Rome, where he studied ancient architecture, including the Pantheon. He made sketches and analyzed classical structures, but the final design of the cathedral’s dome does not replicate the Pantheon’s form. When presenting his idea to Florence’s leadership, including members of the Medici family, he was asked for a model or working plans. Instead, he demonstrated his concept by standing an egg upright, supposedly cracking the shell to show how a vertical structure could support itself.

 

The dome is not a perfect hemisphere but has an ovoid shape, giving it a slightly elongated form. It is divided into eight segments and includes a unique system of double walls. Between the inner and outer walls, Brunelleschi designed an interlocking brick pattern that helped distribute weight evenly. To further support the structure, he incorporated exterior buttressing, including small domes surrounding the base of the main dome. A lantern was later added on top, completing the design.

Study with me on Udemy. (Videos and more.) 

 

If you look at the cutaway of the dome, you can see that it has a double-dome construction. A similar idea was used in the cathedral at Pisa, where a rounded dome was combined with a more pointed one, giving the structure a shape that some have compared to a bottle. In this case, Brunelleschi designed a system of ribs that functioned almost like layers in a laminate countertop. By overlapping wooden beams and using their tensile strength to oppose forces, he created a structure where the ribs pushed outward from the center. This outward force gave the dome a degree of flexibility, which was important in a region like Italy, where earthquakes and shifting ground could pose a problem for large buildings.

Along with these structural ribs, Brunelleschi built an outer dome that enclosed another, slightly more vertical dome inside. He also used a herringbone pattern for the masonry, laying the bricks in an interlocking arrangement that spiraled upward. Laying the bricks this way was difficult, and working at that height added to the challenge. Workers stood on wooden planks attached to temporary platforms, and at times, even Brunelleschi was unsure if the method would succeed.

 

 Instead of using the traditional scaffolding method found in Gothic cathedrals, where bricks were placed on top of a temporary wooden structure, he had to develop a new way to support the bricks as they were laid. Unlike the Pantheon, which may have been filled with sand and had scaffolding built around it, Brunelleschi left the interior space open as the dome was constructed.

Because the double-dome construction created forces that pushed outward, Brunelleschi needed a way to counterbalance them. To do this, he designed a lantern at the top, a structure that looks similar to a miniature Gothic spire. The weight of the lantern pushed down on the oculus at the center of the dome, helping to keep everything stable.

 

To support the lantern placed on top of the dome, Brunelleschi added a series of smaller domes around the base. These structures acted like bookends, pressing against the main dome to provide additional stability. The entire system was designed to work together, and visitors toFlorence can walk between the two domes to see how the structure connects. The design balances tensile strength and flexibility, allowing for movement while maintaining structural integrity.

Some accounts describe additional features that Brunelleschi included, such as small holes drilled in certain areas to allow for expansion and contraction. A book called Brunelleschi’s Dome details some of these techniques, showing how he accounted for forces acting on the structure. His approach combined practical construction knowledge with an understanding of how materials interact over time.

Brunelleschi’s background extended beyond architecture. He was originally trained as a sculptor and had a broad education, including knowledge of biblical texts. His ability to connect different disciplines reflects the Renaissance ideal of a well-rounded individual. Baldassare Castiglione’s book The Book of the Courtier describes the qualities expected of a courtier, including skill in rhetoric, mathematics, art, history, and even physical activities like tennis and weaponry. Brunelleschi shared some of these qualities, as he combined artistic skill with practical engineering.

Study with me on Udemy. (Videos and more.)  

He also applied what would later be called scientific observation. At the time, the idea of systematic experimentation and testing was not as formally established, and the scientific method had not yet been defined. However, Brunelleschi observed architectural principles from ancient buildings, such as the Pantheon, and adapted them for new projects. His approach involved studying past structures, analyzing their construction methods, and applying those ideas to contemporary architecture.