Old Sacristy, 1421-1428
The Old Sacristy is the mausoleum for the Medici family. It is at the south end of the transept in San Lorenzo. The Medici family was the most powerful and influential family in Florence. They were very interested in the cultivation of the arts; for their mausoleum they commissioned Brunelleschi and Donatello. A perfect cube is formed in the sacristy, the walls are equal in height to the sides. The dome is one half the width of the wall and it creates a circle from the square. The Umbrella dome rests on pendentives, which are triangular pieces of vaulting springing from corners used for support.
An Umbrella dome is a hemispherical dome with a circular plan and a ribbed vault.
Brunelleschi used Ionic columns to support entablatures at the doorways, and larger Corinthian columns supporting an entablature that goes around the entire room.
This sacristy is an example of Brunelleschi's mathematical discipline.