The Chapel of the Princes was built during the Baroque period, and is the only Baroque structure in Florence.
The very ornate octagonal chapel was built between 1604-1640, and designed by Giovanni di Medici an amateur architech of sorts,
to reflect the grandeur of the later Medici Grand Dukes of the Baroque period in the 1600's.

The octagonal room designed as a mausoleum for the Grand Dukes of Tuscany.
It is replete with colored marbles enhanced with semi-precious stones
and executed by workers from the Opificio delle Pietra Dure in Florence.
(The Opificio still exists and can be visited to see how this work is accomplished.)
The sarcophagi of the Grand Dukes are in niches in the 8 sides of the room, with its very bigh ceiling.

The Chapel of the Princes is located in the area behind San Lorenzo, in the same structure housing
the New Sacristy Medici Tombs with Michelangelo's figures of Dawn and Dusk and Night and Day.