Ornamentation and Plan - Pazzi Chapel (2005)
In the design of the Pazzi Chapel in Florence, Filippo Brunelleschi was immensely concerned with the relationship between the domed ceiling and the plan of the building. Such a relationship is taken to the extent that in his choice of interior ornamentation, he tries to emphasize the layout of the plan through the decorative elements.

The Pazzi Chapel consists of two domes, a large one which sits above the central space and a smaller one that rests on top of the choir in the back. Upon entering the main space from the porch, itself decorated by six Corinthian columns with matching pilasters on the outside wall, one is greeted with the same decorative pilasters as on the exterior. Brunelleschi, in his choice of ornamentation, uses these pilasters to identify the square area on the floor which lies directly underneath the dome, thus creating an aesthetic connection between the top and bottom of the building. These pilasters not only direct the attention upwards towards the base of the archway that forms a visual supporting base for the dome, but also generates interest in the proportion of the plan and its relationship to the domed ceiling. The four pilasters that form the corners of the square from which the dome sits point interest towards the carefully calculated and proportioned sides of the quadrilateral, a feature that Renaissance architecture is known to place highly.

A total of sixteen pilasters line the walls of the central space. Four of those have already been mentioned to be space dividers for the dome, setting off an invisible parameter to the ceiling space. In the other pilasters along the longer side of the rectangular wall, two of them are used to mark the base of the archway that sits above the entrance from the porch and towards the choir. The other two stand against the corner towards the other wall of the central space. The importance of these pilasters lie not only in their reflection of the exterior façade, but also in their demonstration of the clever mathematical calculations that has been employed by the architect to ensure a proportional space. Along the shorter wall of the central space, two lone pilasters exist to form the supporting base of the small arch that echoes the outline of the barrel-vault on either side of the dome, placed in a set order to fit perfectly within the space.

The fact that an elongated square is used for the central space instead of a perfect square could be seen as an action that emphasizes the proportionality of space in the centre of the room. By creating excess space on either sides of the square in the centre of the plan, Brunelleschi is defining a contrast in the barrel-vaulted ceiling, a source of comparison to the ideal shape of the circular dome. It also establishes a place for people within the building to view the central space, a viewing platform away from the space of discussion.

Like all Renaissance architects, there is a desire by Brunelleschi to achieve a symmetry within his design. In his decorative ornamentation, he creates what essentially are window frames on the side of the wall opposite from the one facing the porch, as a reflection of the windows that bring light into the building. In effect, they stress the order and mathematical relation of the building, similar to the functions of the pilasters.

Brunelleschi’s Pazzi Chapel is characteristic of Renaissance architecture in many ways. Its attention to the mathematical relationship and proportionality is underlined by the orderly ornamentation. Elements which define the relationship between the dome, the plan and the ornamentation can be seen throughout the design, such as in the contrasting space he creates with the barrel-vaulted ceilings on either side of the dome. The ornamentation and the plan draw a relationship where one supports and raises attention to the other in a subtle manner.