The central space conceived by Brunelleschi is a rather small, squared room, yet it is extremely elegant geometrically. To see this in context, compare the dimensions of the New Sacristy of the Medici church San Lorenzo (1422-1428) to the sacristies of the gothic Florentine basilicas that were much bigger in size, like Santa Croce, Santa Maria Novella. Squares (cube) and circles (sphere) are the geometric forms that are immediately perceivable. These are important elements that regulate and organize the space, just like in the Loggia degli Innocenti. The spatial structure is achieved by the pilasters, the trabeation, the archways, and the crests of the cover, all of which are in pietra serena and ennobled by classical elements that delineate the areas of white plaster. The other architectural elements are: the windows, the medallion, the niche at the altar. The main framework lines are archived in way that their position is clearly determined. Manetti had spoken about the novelty of the New Sacristy at the time, which was based on a new model and architectural language: ‘It amazed all Men, both residents and foreigners, who had to see it for its new form and beauty. There were so many people who came to see it that all these visitors bothered the workers as they were building it”.
The Pazzi Chapel in Santa Croce (circa 1429) was born as chapter house with a chapel behind the main altar, where the Medici tombs are located. The size of the chapel can be seen in comparison to the mass of the Arnolfo church. It is seen as a structure that does not need to develop large spaces in order to be considered a perfect spatial model, characterized by ‘pure’ regularity and geometry. The layout is essentially the same as that of the Old Sacristy, but it is much more articulated: the major room, which is squared and covered with a cupola, is enlarged laterally with two small wings, covered with barrel vaults.
Source APT Florence