The Medici Chapels are a complex of chapels of great historical and architectural interest. Situated on the ground floor is the Crypt, which holds the tombs of some of the more minor members of the Medici family, was built following a design by Buontalenti.
The Cappelle Medicee or Medici Chapels, consist of three sections, the Chapel of the Princes, the New Sacristy, and the Crypt. Although the Cappelle Medicee is directly connected to the church of San Lorenzo, access is from the Piazza Madonna degli Aldobrandini. The entrance is not particularly obvious due to the presence of the San Lorenzo street market.
From the Crypt, stairs lead up to the Chapel of Princes, a grand mausoleum for the Medici grand dukes. Work stated on the chapel in 1604 based on a design by Don Giovanni de' Medici, although later a number of major alterations to this design was made by Buontalenti. The Chapel of Princes is octagonal in shape, clad in dark marble and pietra dura. Here can be seen the coats of arms of sixteen Tuscan towns, constructed using pietra dura, mother-of-pearl, lapis lazuli, and coral inlays.
Lining the walls are six sarcophagi belong to grand dukes Ferdinando II, Cosimo II, Ferdinando I, Cosimo I, Francis I and Cosimo III. The sarcophagi of Cosimo II and Ferdinando I, are adorned by huge bronze statues.
The New Sacristy was commissioned by Cardinal Giulio de' Medici and Pope Leo X, to be the funerary chapel for the Medici family. Michelangelo was commissioned to carry out the work, which commenced in 1521, but almost ground to a halt during the siege of Florence, which also saw the Medici family being expelled from the city for a period of time. In 1534 Michelangelo left Florence, never to return, and by this time only the tombs of Lorenzo, Duke of Urbino, and Giuliano de' Nemours had been completed.